Maneuvering robotic vehicles having a positionable sensor head

This application claims the benefit of U.S. Provisional Application Ser. No. 60/883,731, filed on Jan. 5, 2007, which claims the benefit of U.S. Provisional Application Ser. No. 60,828,611 filed on Oct. 6, 2006, the contents of which are hereby incorporated by reference for all purposes.

STATEMENT AS TO FEDERALLY SPONSORED RESEARCH

This invention was made in part with Government support under contract DAAE07-03-9-F001 awarded by the Technical Support Working Group of the Department of Defense. The Government may have certain rights in the invention.

TECHNICAL FIELD

This invention relates to robotics, and more particularly to mobile robots or vehicles capable of climbing by shifting their center of gravity.

BACKGROUND

Robots are useful in a variety of civilian, military, and law enforcement applications. For instance, some robots may inspect or search buildings with structural damage caused by earthquakes, floods, or hurricanes, or inspect buildings or outdoor sites contaminated with radiation, biological agents such as viruses or bacteria, or chemical spills. Some robots carry appropriate sensor systems for inspection or search tasks. Robots designed for military applications may perform operations that are deemed too dangerous for soldiers. For instance, the robot can be used to leverage the effectiveness of a human “pointman.” Law enforcement applications include reconnaissance, surveillance, bomb disposal and security patrols.

Small, man-portable robots are useful for many applications. Often, robots need to climb stairs or other obstacles. Generally, a small robot must span at least three stair corners to climb stairs effectively, and must have a center of gravity in a central disposition to maintain climbing stability. When the size or length of a robot reaches a certain small size relative to the obstacle or stair it must climb, the robot's center of gravity usually has a deleterious effect on climbing ability. What is needed, therefore, is a robot design that can climb obstacles that are large relative to the size of the robot.

Such robots are also employed for applications that require a robot to inspect under and around various objects and surfaces. What is needed, therefore, are robot sensor heads moveable in various degrees of freedom.

SUMMARY

Various robot head and neck morphologies are provided to allow positioning for various poses such as a stowed pose, observation poses, and inspection poses. Neck extension and actuator module designs are provided to implement various head and neck morphologies. Robot actuator control network circuitry is also provided.

One preferred embodiment is a robot including a chassis having a central open volume, a steerable drive supporting the chassis, and neck extension movable be coupled to the chassis, and a pan link extension having proximal and distal ends being coupled to the neck extension at the proximal end with a first tilt access actuator. The pan link extension has a one axis actuator along its length. A sensor head is coupled to a distal end of the pan link extension. The sensor head as movable using the axes.

Preferred actuator designs provide and actuator module, the module including the actuator motor, control circuitry for the motor, a slip ring and having multiple concentric conductive traces which matched to corresponding contacts on an electrical contact board rotatable with respect to the slip ring.

Configurations are provided for vehicular robots or other vehicles to provide shifting of their center of gravity for enhanced obstacle navigation. In preferred embodiments, a robot chassis with articulated driven flippers has an articulated neck and articulated sensor head mounted toward the front of the chassis. The articulated neck is pivoted forward to shift the vehicle combined center of gravity (combined CG) forward for various climbing and navigation tasks. Flippers may also be employed with the CG shifting effect of moving flippers added to that of the pivoting head and neck. Various embodiments may have different weight distributions to allow different CG shifting capabilities.

One preferred embodiment includes a chassis supporting a skid steered drive and having a leading end, a trailing end, and a chassis center of gravity (chassis CG) therebetween, a set of driven flippers, an articulated neck and an articulated sensor head the chassis, set of flippers, neck, and articulated sensor head adapted to move and thereby produce a corresponding adjustment in the vehicle center of gravity. Such adjustment may be employed to allow stair climbing, obstacle navigation, crevasse navigation, or other desired operations. The articulated neck may include a pan axis element.

Robots according to various morphologies may be positioned in various poses suitable to accomplish their mission. A preferred control scheme provides preset poses in response to certain operator commands. Preset CG shifting poses and preset observation or inspection poses are provided.

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

<figref idrefs="DRAWINGS">FIG. 1</figref> shows robot with extendable arms or flippers.

<figref idrefs="DRAWINGS">FIG. 2</figref> depicts one method by which a robot may climb stairs.

<figref idrefs="DRAWINGS">FIG. 3</figref> shows another exemplar tracked vehicle robot.

<figref idrefs="DRAWINGS">FIG. 4</figref> depicts another tracked robot vehicle.

<figref idrefs="DRAWINGS">FIG. 5</figref> depicts a side representation of another robot.

<figref idrefs="DRAWINGS">FIG. 6</figref> depicts a robot vehicle encountering an obstacle under two different scenarios.

<figref idrefs="DRAWINGS">FIG. 7</figref> depicts a robot vehicle having flippers residing within the length of the vehicle.

<figref idrefs="DRAWINGS">FIG. 8</figref> depicts a robot using flippers to mount an obstacle backwards.

<figref idrefs="DRAWINGS">FIG. 9</figref> shows and example of how a pivotable neck and sensor head contribute significant CG shifting ability.

<figref idrefs="DRAWINGS">FIG. 10</figref> depicts elevated neck positions for two configurations.

<figref idrefs="DRAWINGS">FIG. 11</figref> depicts a robot in various positions crossing a crevasse.

<figref idrefs="DRAWINGS">FIG. 12</figref> depicts another robot CG shifting technique.

<figref idrefs="DRAWINGS">FIG. 13</figref> is a flow chart of a method of ascending an obstacle.

<figref idrefs="DRAWINGS">FIG. 14</figref> shows a robot having a wheel drive.

<figref idrefs="DRAWINGS">FIG. 15</figref> depicts a robot in a stowed configuration.

<figref idrefs="DRAWINGS">FIG. 16</figref> depicts a perspective view of another robot vehicle.

<figref idrefs="DRAWINGS">FIG. 17</figref> depicts the robot of <figref idrefs="DRAWINGS">FIG. 16</figref> in a climbing configuration.

<figref idrefs="DRAWINGS">FIG. 18</figref> depicts another robot in a stair climbing position with a forward-shifted combined CG.

<figref idrefs="DRAWINGS">FIG. 19</figref> depicts another robot in a stair descending position. In this configuration the robot has chassis pointing downward.

<figref idrefs="DRAWINGS">FIG. 20</figref> depicts a robot climbing an obstacle forward.

<figref idrefs="DRAWINGS">FIG. 21</figref> shows a robot mounting an obstacle backwards.

<figref idrefs="DRAWINGS">FIG. 22</figref> shows a robot with a four degree of freedom system for positioning a sensor head.

<figref idrefs="DRAWINGS">FIG. 23</figref> shows a robot with four degrees of freedom and a “pan-link” section for positioning a head.

<figref idrefs="DRAWINGS">FIG. 24</figref> shows a robot that implements a possible four degree of freedom system for positioning a head employing another joint morphology.

<figref idrefs="DRAWINGS">FIG. 25</figref> shows another robot that implements a possible four degree of freedom system for positioning a head employing another joint morphology.

<figref idrefs="DRAWINGS">FIG. 26</figref> shows another robot that implements a possible four degree of freedom system for positioning a head using a joint morphology that includes a 45-degree link.

<figref idrefs="DRAWINGS">FIG. 27</figref> illustrates a possible configuration of a preferred design for a neck extension and actuator assembly.

<figref idrefs="DRAWINGS">FIG. 28</figref> illustrates a cutaway view of a possible embodiment of the actuator assembly of <figref idrefs="DRAWINGS">FIG. 27</figref>.

<figref idrefs="DRAWINGS">FIG. 29</figref> depicts a cutaway view of a possible embodiment of a first tilt axis of the actuator assembly of <figref idrefs="DRAWINGS">FIG. 27</figref>.

<figref idrefs="DRAWINGS">FIG. 30</figref> depicts another cutaway view of a possible embodiment of a first tilt axis of the actuator assembly of <figref idrefs="DRAWINGS">FIG. 27</figref>.

<figref idrefs="DRAWINGS">FIG. 31</figref> depicts yet another cutaway view of a possible embodiment of a first tilt axis of the actuator assembly of <figref idrefs="DRAWINGS">FIG. 27</figref>.

<figref idrefs="DRAWINGS">FIG. 32</figref> illustrates a cutaway view of a possible embodiment of a second tilt axis of the actuator assembly of <figref idrefs="DRAWINGS">FIG. 27</figref>.

<figref idrefs="DRAWINGS">FIG. 33</figref>, illustrates a cutaway view of a possible embodiment of a neck attachment or “shoulder” axis of the actuator assembly of <figref idrefs="DRAWINGS">FIG. 27</figref>.

<figref idrefs="DRAWINGS">FIG. 34</figref> illustrates another cutaway view of a possible embodiment of a neck attachment or “shoulder” axis of the actuator assembly of <figref idrefs="DRAWINGS">FIG. 27</figref>.

<figref idrefs="DRAWINGS">FIG. 35A</figref> depicts an exploded perspective view of a neck extension connector.

<figref idrefs="DRAWINGS">FIG. 35B</figref> depicts another exploded perspective view of a neck extension connector.

<figref idrefs="DRAWINGS">FIG. 35C</figref> depicts a perspective view of an assembled and latched neck extension connector.

<figref idrefs="DRAWINGS">FIG. 36</figref> illustrates a block diagram of a robot sensor head.

<figref idrefs="DRAWINGS">FIG. 37</figref> illustrates a block diagram of a robot neck tilt module.

<figref idrefs="DRAWINGS">FIG. 38</figref> illustrates a block diagram of a robot neck pan module.

<figref idrefs="DRAWINGS">FIG. 39</figref> illustrates a block diagram of a robot neck attachment tilt module.

<figref idrefs="DRAWINGS">FIG. 40</figref> illustrates a block diagram of circuit components in robot chassis or base.

<figref idrefs="DRAWINGS">FIG. 41</figref> shows a robot using an extended pan-link section in a low profile pose.

<figref idrefs="DRAWINGS">FIG. 42</figref> shows a robot in a pose for looking through windows.

<figref idrefs="DRAWINGS">FIG. 43</figref> shows a robot in a pose for observing underneath its supporting surface.

<figref idrefs="DRAWINGS">FIG. 44</figref> shows a robot in a pose for looking around a corner.

<figref idrefs="DRAWINGS">FIG. 45</figref> shows a robot in an alternate low profile pose.

<figref idrefs="DRAWINGS">FIG. 46</figref> shows a robot in an under vehicle self-inspection pose.

<figref idrefs="DRAWINGS">FIG. 47</figref> shows a robot in another self-inspection pose.

<figref idrefs="DRAWINGS">FIG. 48</figref> shows a robot in a high profile observation pose.

<figref idrefs="DRAWINGS">FIG. 49</figref> shows a robot in a pose for inspecting under low obstacles.

<figref idrefs="DRAWINGS">FIG. 50</figref> depicts a flow chart for moving to preset positions.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

Various tracked robotic vehicles have been developed that are the subject of, for example, U.S. Pat. Nos. 6,431,296, 6,263,989, 6,668,951 and 6,651,885. These patents are instructive on the construction of tracked robotic vehicles having driven flippers, and means of articulation of robotic components, and are hereby incorporated by reference in their entirety into this application. Other robotic vehicle details and features combinable with those described herein may be found in a U.S. Provisional application, filed Oct. 6, 2006, and assigned Ser. No. 60/828,606, the entire contents of which are hereby incorporated by reference.

<figref idrefs="DRAWINGS">FIG. 1</figref> shows robot <b>100</b> with extendable arms or flippers <b>130</b>. The arms are shown fully extended configuration in which forward arms <b>130</b> extend beyond the front of main body <b>140</b>. The combination of forward tracks <b>120</b> and main tracks <b>110</b> and provide an extended length base. Main body <b>140</b> includes a vertically symmetrical rigid frame <b>310</b>, which includes parallel vertical side plates <b>312</b>. Side plates <b>312</b> are rigidly coupled by tubes <b>320</b>, <b>322</b>, and an articulator shaft <b>330</b>. The rigid components are designed for strength and low weight and are preferably made from a material such as 7075-T6 aluminum. Alternative versions of the robot can use other materials, such as other lightweight metals, polymers, or composite materials.

Alternative versions of the robot can use other types of tracks, such as tracks made up of discrete elements. However, debris may be caught between elements and such tracks are generally heavier than flexible belts. Other flexible materials can also be used for continuous belt tracks. Referring back to <figref idrefs="DRAWINGS">FIG. 1</figref>, in this embodiment, each front track <b>120</b> is narrower but otherwise similar to main tracks <b>110</b>, having grooves and a V-shaped segment on the inside surface, and soft cleats <b>350</b> attached to the outside surface. A front drive pulley <b>344</b> drives each front track <b>120</b>. Each front drive pulley <b>344</b> is toothed and has a central V-shaped channel that loosely mates with the V-shaped rib on the inside of the corresponding front track <b>120</b>. On each side, front drive pulley <b>344</b> is coaxial with main drive pulley <b>342</b>, and both drive pulleys on a particular side turn in unison on a common axle. A smaller smooth surfaced front idler puller <b>346</b>, which also has a V-shaped channel, supports each front track <b>120</b> at the extreme end of the corresponding arm <b>130</b>.

As depicted in <figref idrefs="DRAWINGS">FIG. 1</figref>, front tracks <b>120</b> are supported by arm side plates <b>332</b> using front track supports <b>334</b>. Front track supports <b>334</b> are wedge-shaped and each has a series of angled slots similar to those in main track supports <b>314</b>. The arm side plates <b>332</b> on each side of the robot are rigidly coupled to one another through articulator shaft <b>330</b>, and therefore move together.

Other designs may be employed to produce a robot with such a skid steered drive and driven flippers. For example, some embodiments may employ techniques taught in the various U.S. patents that are incorporated by reference herein.

<figref idrefs="DRAWINGS">FIG. 2</figref> depicts one method by which robot <b>100</b> may climb stairs. The depicted robot <b>100</b> can raise arms <b>130</b> in order to mount an obstacle, such as a stair <b>1010</b>, in its path. To mount the first step of staircase <b>1010</b>, robot <b>100</b> raises its arms <b>130</b> and drives forward to raise its main tracks <b>110</b> onto the first stair. The robot then assumes a fully extended mode thereby extending its wheelbase to increase it stability and to provide as smooth a ride a possible up the stairs. Cleats (not shown in <figref idrefs="DRAWINGS">FIG. 2</figref>) provide mechanical locking with the stair edge needed to drive the robot up the stairs.

One embodiment of the robot <b>100</b> may be specifically dimensioned to climb common stairs, with step dimensions of up to a 17.8 cm (7-inch) rise and 27.9 cm (11-inch) tread. As the robot tilts or inclines, the vertical projection of the center of gravity (CG) with respect to the ground moves backwards. For stable travel on stairs, the extended wheel base of the main and forward tracks in the fully extended mode span a minimum of two steps (i.e. at least 66.2 cm for 17.8 cm by 27.9 cm stairs) such that the vehicle is supported by at least two stair treads at all times. Note that the depicted robot <b>100</b> can climb larger stairs for which it cannot span two steps, but the traverse will not be as smooth as the robot will bob with each step.

To avoid nosing up or down (pitch instability) while climbing stairs, the vertical projections of the center of gravity is located in a stable range which is at least one step span (i.e., 33.1 cm (13 inches) for 17.8 cm by 27.9 cm stairs) in front of the furthest rear main track ground contact <b>160</b> and at least one step span behind the front most front track ground contact <b>180</b>.

Alternative versions of the robot can use shorter track dimensions that do not satisfy the requirement of spanning two steps. Without further modifications, however, the center of gravity can be outside the stable range. Such robots may not be as stable on stairs, although inertial effects add to dynamic stability at increased velocities, smoothing the traverse on stairs. Various methodologies may be used to mitigate this and other climbing and terrain traversing problems. Below we describe different embodiments (having different morphologies) for a basic small tracked vehicle system that may have enhanced capability to climb or traverse.

<figref idrefs="DRAWINGS">FIG. 3</figref> shows an exemplar tracked vehicle robot. The depicted system is primarily comprised of four parts: 1) a main tracked vehicle chassis <b>301</b>, 2) a “flipper” tracks <b>302</b> on one end of the vehicle, 3) a sensor head <b>303</b> preferably containing drive cameras and other sensors <b>304</b>, and 4) a neck mechanism <b>305</b> that connects head <b>303</b> to chassis <b>301</b>. Many improved robotic, vehicle designs may be derivative of this basic platform design. Various designs may be required to carry various payloads such as sensors, transmission equipment, or robotic tools, for example.

The tracked vehicle robot may be required to surmount a variety of obstacles that will require the vehicle center of gravity (CG) to fall within a certain range. These obstacles include, for example, stairs, single vertical steps, and slopes. Included herein are tracked-vehicle morphology capable of meeting these “primary” requirements. Because tracked vehicle robots may be subject to both stringent overall weight and stowed size requirements, it is desirable to be able to negotiate these obstacles with the smallest sized vehicle possible such that these constraints can be met as well. To do this reliably, it is also desirable to achieve all of this with the simplest system possible. Likewise, power consumption of the drive train must be considered to meet varied endurance requirements. Further, the system may be required to elevate the drive sensors <b>304</b> to a specific height which may play an important factor is being able to shift the CG to be able to negotiate extreme obstacles.

A typical such obstacle is the ability to climb standard stairs with 7-inch risers by 11-inch landings, for climbing higher obstacles. Climbing slopes is sometimes required. These requirements typically need to be met while minimizing weight, and size for portability, maximizing vehicle endurance, and accommodating extra payloads for certain scenarios. Some small tracked vehicle robots require a minimum drive sensor height above the ground to see over obstacles.

<figref idrefs="DRAWINGS">FIG. 4</figref> depicts another tracked robot vehicle. In this example, neck <b>305</b> is attached to chassis centrally, rather than to a vertical wall of the track drive (<figref idrefs="DRAWINGS">FIG. 3</figref>). The actuator motor <b>306</b> in is shown mounted to chassis <b>301</b>, but may also be provided in a flush housing or other mounting arrangement. Actuator <b>306</b> may be powerful enough to move neck and head designs with significant mass for center of gravity shifting (CG shifting) or other applications. Neck <b>305</b> may also be provided with tapped holes or other fittings to attach various payloads. Neck <b>305</b> may also be relatively much larger in diameter than depicted to provide for housing various components or payloads. Actuators may be backdriveable or non-backdriveable, which may depend on the types of tasks desired for neck <b>305</b>. Further, while track-driven robots are shown, other drive means may be used such as wheels. Closely spaced or overlapping treaded wheels may be used to provide mobility and climbing capability similar to that of a track drive. Such variations typically encompass the main drive, while preferred flippers use tracks. The flipper and chassis track systems may be compliant tracks or rigid sectional tracks.

Depicted in <figref idrefs="DRAWINGS">FIG. 4</figref> is a payload storage opening in chassis <b>301</b>. For “head-forward” embodiments such as those in <figref idrefs="DRAWINGS">FIG. 3</figref> and <figref idrefs="DRAWINGS">FIG. 4</figref>, payload storage is preferably at or toward the front of chassis <b>301</b>. Preferably such storage resides close to the center of the track footprint so as not to adversely affect CG shifting, capability as described herein. Payloads may of course also be housed in the track housings on both sides of the chassis, and in or on the neck and head. In some embodiments chassis <b>301</b> is configured as depicted with a payload deck, and others may have different structures. Chassis <b>301</b> may be provided with tapped holes to accept cargo attachment or fixture attachment. Chassis <b>301</b> may also be provided with stowage space or a slot for neck <b>305</b> to stow into while in a stowed position such as, for example, P<b>5</b> depicted in <figref idrefs="DRAWINGS">FIG. 9</figref>. Head <b>303</b> may also be provided with a slot and recessed articulation joint to lower the profile of the head and neck in stowed position. To protect the head, it must stow as much as possible within the profile of the tracks. In one preferred embodiment, the head will approximately be at least 1.5 inches thick; likewise, the neck and its pan/tilt actuators will probably require at least another 1.5 inches under the head when stowed. Since the track wheel pitch diameter will be around 5 inches, and a typical flipper torque tube will be about 0.75 inch diameter (delivering torque from a flipper actuator), this only leaves a little over 2 inches for the head and neck to stow. Therefore, it will probably not be possible for the head to stow both over the torque tube and remain within the track volume.

Chassis <b>301</b> is preferably constructed of strong lightweight materials, and may include a shell around an enclosed volume. A structural volume housing electronics may also support the necessary load paths of the system. In the simplest case where the chassis is modeled as a hollow box, there is adequate strength to also support wheels and running gear on the sides of this box.

Some characteristics for three different embodiments are described below. Note that the values depicted are for one possible morphology and that other morphologies can be derived by reallocating weights from one component to another. For example, in typical examples the flippers will be about 10% of the total robot weight. To provide heavier flippers (say by moving the batteries to the flippers), the battery weight (which is typically around 23% but may vary greatly) would be subtracted out of the chassis and added to the flippers, thus making the flippers contain about 33% of the total robot weight. Further, partial battery capacity may be shifted to the robot head for a heavier head providing, in some designs, an improved CG shifting capability. For example, some designs herein have a head with 15% of the overall robot weight. Designs that provide battery capacity located in the robot sensor head and neck may provide head weight ranging as high as around 17%, 20%, or even 22% or 25%, depending on CG shifting requirements and design constraints. Likewise, a lighter head can be employed if certain components like cameras or transmission gear are removed.

One embodiment of the robot depicted in <figref idrefs="DRAWINGS">FIG. 3</figref> and <figref idrefs="DRAWINGS">FIG. 4</figref> has the following characteristics, preferred for CG shifting in certain scenarios.

<tables id="TABLE-US-00001" num="00001"><table frame="none" colsep="0" rowsep="0"><tgroup align="left" colsep="0" rowsep="0" cols="1"><colspec colname="1" colwidth="217pt" align="center" /><thead><row><entry namest="1" nameend="1" rowsep="1">TABLE 1</entry></row></thead><tbody valign="top"><row><entry namest="1" nameend="1" align="center" rowsep="1" /></row><row><entry>Weight Distribution for Design 1.</entry></row></tbody></tgroup><tgroup align="left" colsep="0" rowsep="0" cols="4"><colspec colname="offset" colwidth="14pt" align="left" /><colspec colname="1" colwidth="49pt" align="left" /><colspec colname="2" colwidth="63pt" align="left" /><colspec colname="3" colwidth="91pt" align="center" /><tbody valign="top"><row><entry /><entry>Component:</entry><entry>Component Weight:</entry><entry>Percentage of overall wt:</entry></row><row><entry /><entry namest="offset" nameend="3" align="center" rowsep="1" /></row><row><entry /><entry>Chassis</entry><entry> 21 lbs</entry><entry>70</entry></row><row><entry /><entry>Flippers</entry><entry>  3 lbs</entry><entry>10</entry></row><row><entry /><entry>Head</entry><entry>4.5 lbs</entry><entry>15</entry></row><row><entry /><entry>Neck</entry><entry>1.5 lbs</entry><entry> 5</entry></row><row><entry /><entry>Payload</entry><entry>  6 lbs (rating)</entry><entry>additional</entry></row><row><entry /><entry namest="offset" nameend="3" align="center" rowsep="1" /></row></tbody></tgroup></table></tables>

The weights and ratios provided may vary slightly and still provide the desired capabilities. Such embodiment also has physical parameters as follows. Track wheel diameter of about 5 inches; chassis length about 17 inches; flipper length about 9.5 inches; and neck length about 17 inches. Such design provides ability to scale an obstacle in the forward direction having an 11.4 inch height. While these designs have been provided, size and weight ratios may change slightly and still provided the desired climbing and maneuvering enhancements. The three designs herein have been configured to crest standard stair and obstacles in a manner such as depicted in <figref idrefs="DRAWINGS">FIGS. 18-21</figref>, for example, while still maintaining a robot that can stow flippers and neck to fold into a small, man portable shape. For larger obstacles, the ratios given herein may be scaled appropriately and other ratios may be used successfully with the CG shifting techniques taught herein.

Another embodiment of the robot depicted in <figref idrefs="DRAWINGS">FIG. 3</figref> and <figref idrefs="DRAWINGS">FIG. 4</figref> has the following characteristics, preferred for CG shifting in certain other scenarios.

<tables id="TABLE-US-00002" num="00002"><table frame="none" colsep="0" rowsep="0"><tgroup align="left" colsep="0" rowsep="0" cols="1"><colspec colname="1" colwidth="217pt" align="center" /><thead><row><entry namest="1" nameend="1" rowsep="1">TABLE 2</entry></row></thead><tbody valign="top"><row><entry namest="1" nameend="1" align="center" rowsep="1" /></row><row><entry>Weight Distribution for Design 2</entry></row></tbody></tgroup><tgroup align="left" colsep="0" rowsep="0" cols="4"><colspec colname="offset" colwidth="14pt" align="left" /><colspec colname="1" colwidth="49pt" align="left" /><colspec colname="2" colwidth="63pt" align="left" /><colspec colname="3" colwidth="91pt" align="center" /><tbody valign="top"><row><entry /><entry>Component:</entry><entry>Component Weight:</entry><entry>Percentage of overall wt:</entry></row><row><entry /><entry namest="offset" nameend="3" align="center" rowsep="1" /></row><row><entry /><entry>Chassis</entry><entry>19.5 lbs</entry><entry>65</entry></row><row><entry /><entry>Flippers</entry><entry>  3 lbs</entry><entry>10</entry></row><row><entry /><entry>Head</entry><entry> 4.5 lbs</entry><entry>15</entry></row><row><entry /><entry>Neck</entry><entry>  3 lbs</entry><entry>10</entry></row><row><entry /><entry>Payload</entry><entry>  6 lbs (rating)</entry><entry>additional</entry></row><row><entry /><entry namest="offset" nameend="3" align="center" rowsep="1" /></row></tbody></tgroup></table></tables>

Table 2: Weight Distribution for Design 2

This design has similar size parameters to the first listed design, Design 1. Because it is not desired to add “dead weight” or useless weight, the additional neck weight is preferably a result of attaching payloads to the neck or housing payloads inside the neck, as discussed above. This may be desired, for example, to provide camera or RF surveillance equipment, or other sensors, and recording transmission electronics that are spaced above the ground for optimum propagation characteristics. This configuration allows for CG shifting to enable addressing obstacles of about 15.1 inches in one direction, and 11.6 inches in both directions.

<figref idrefs="DRAWINGS">FIG. 5</figref> depicts a side representation of another robot. In this robot, lightweight flippers <b>502</b> are provided on both ends of chassis <b>501</b>. Preferably, the lightest feasible head <b>303</b> is assumed to offset the extra weight of the rear flippers <b>502</b>. Chassis <b>501</b> is assumed to be slightly shorter than that in the previous embodiment since it is not needed for stability and may be necessary to additionally offset more weight for actuator and extra battery weight, (due to added power draw from the extra flipper). Such design has a center of gravity (CG) at the mark CG<b>50</b> when resting in the depicted position. The added length due to the extra flipper also provides a longer range of locations on which payloads can be mounted without overly shifting the vehicle CG.

<tables id="TABLE-US-00003" num="00003"><table frame="none" colsep="0" rowsep="0"><tgroup align="left" colsep="0" rowsep="0" cols="1"><colspec colname="1" colwidth="217pt" align="center" /><thead><row><entry namest="1" nameend="1" rowsep="1">TABLE 3</entry></row></thead><tbody valign="top"><row><entry namest="1" nameend="1" align="center" rowsep="1" /></row><row><entry>Weight Distribution for Design 3.</entry></row></tbody></tgroup><tgroup align="left" colsep="0" rowsep="0" cols="4"><colspec colname="offset" colwidth="14pt" align="left" /><colspec colname="1" colwidth="49pt" align="left" /><colspec colname="2" colwidth="63pt" align="left" /><colspec colname="3" colwidth="91pt" align="center" /><tbody valign="top"><row><entry /><entry>Component:</entry><entry>Component Weight:</entry><entry>Percentage of overall wt:</entry></row><row><entry /><entry namest="offset" nameend="3" align="center" rowsep="1" /></row><row><entry /><entry>Chassis</entry><entry> 22 lbs</entry><entry>73 </entry></row><row><entry /><entry>Flippers</entry><entry>  3 lbs</entry><entry>10 each set</entry></row><row><entry /><entry>Head</entry><entry>1.2 lbs</entry><entry>4</entry></row><row><entry /><entry>Neck</entry><entry>0.9 lbs</entry><entry>3</entry></row><row><entry /><entry>Payload</entry><entry>  6 lbs (rating)</entry><entry>additional</entry></row><row><entry /><entry namest="offset" nameend="3" align="center" rowsep="1" /></row></tbody></tgroup></table></tables>

The preferred implementation of design 3 also has the following physical parameters: wheel diameter, 5 inches; chassis length, 15 inches; flipper length, 9.5 inches; and neck length, 15 inches. Such parameters provide ability to scale a forward obstacle of 13.8 inches height when using the CG shifting techniques described herein.

While several design variations with different parameters are described, variations in size are accommodated for robots with different intended purposes. The designs included are intended to provide small robots, that are man-portable yet capable of climbing stairs. Larger robots, or other vehicles, may have little trouble climbing stairs, but may use the CG shifting techniques described, herein to enable crossing crevasses, larger obstacles, or other purposes.

<figref idrefs="DRAWINGS">FIG. 6</figref> depicts a robot vehicle encountering an obstacle under two different scenarios. Regarding stairs and obstacles, the first step in negotiating any obstacle is to make sure the vehicle can transition up, the obstacle from a flat surface. For example, if the vehicle encounters a vertical wall but cannot at least get the front of the vehicle to climb it, the vehicle typically will not be able to handle any obstacles that are more than one wheel radius. Preferably, the vehicle CG should be as close to the rear axle as possible and the front of the vehicle should encounter the obstacle as high as possible. On top of this, many obstacles may be undercut such that the vehicle may wedge under it (such as fire-escape stairs as depicted in <figref idrefs="DRAWINGS">FIG. 6</figref><i>a</i>), so having a very high approach point is important (large Y dimension). Also, note that such obstacles result in a downward force being applied to the front of the vehicle unless there is some feature on the vehicle that can change this contact angle. It is for these reasons (among others) that the tracked vehicle robot systems preferably have flipper tracks on one end of the vehicle which can be rotated to any orientation, and that this is considered the “front” of the robot. This is depicted in <figref idrefs="DRAWINGS">FIG. 6</figref><i>b</i>. For clarity, the end of the vehicle with flippers <b>602</b> attached is defined as the “front,” but a vehicle may be run “backwards” to scale obstacles if this proves beneficial in some cases.

<figref idrefs="DRAWINGS">FIG. 7</figref> depicts a robot vehicle having flippers residing within the length of the vehicle. Such flippers greatly enhance the ability of a small vehicle to scale large objects relative to it size. This is not only due to the reasons above, but also because they increase the vehicle's footprint for a given stowed volume (since the flippers can be folded beside the vehicle when stowed, but can be deployed as necessary for a given obstacle). Flippers also are sometimes employed to right the vehicle when it is inverted. To do so, the vehicle CG must reside within the length of the flipper when it is stowed as shown in <figref idrefs="DRAWINGS">FIG. 7</figref>.

Assuming the chassis density is somewhat uniform (resulting in its CG being at its geometric center), and the flippers would shift the CG slightly off to the end to which they are mounted, this implies that the flippers typically not be shorter than about 50% of the chassis length. Therefore having the flippers be at least 50% of the chassis length is a good baseline unless the flippers are adapted to have more weight (in which case they could be slightly shorter).

It is also important for the flippers to spin 360 degrees continuously in either direction. This not only is necessary to recover from being inverted, but it also considerably adds to the vehicle mobility over very level and unstable terrain (such as rocks or tall grass). With such movement, the flippers may also act as arms to help pull the vehicle over such terrains.

Depending on what vehicle morphology is employed and where the average CG location is located, the vehicle may be able to surmount larger obstacles backwards than it can forwards. This happens when the vehicle, CG is shifted aft and thus the lightweight flippers can be used to elevate the CG over the obstacle. By using the flippers to achieve “prairie-dog” pose (driving on the flipper tracks only), large obstacles can be approached backwards as depicted in <figref idrefs="DRAWINGS">FIG. 8</figref>. The flippers are then rotated to lift the front of the vehicle up to help scale the obstacle.

As described above, due to the limitations of the design in <figref idrefs="DRAWINGS">FIG. 8</figref>, an articulated neck may also be added at the back of the robot. In such embodiments, the neck may be moved to adjust the center of gravity (CG) of the robot and optimize obstacle scaling ability.

<figref idrefs="DRAWINGS">FIG. 9</figref> shows and example of how a pivotable neck and sensor head contribute significant CG shifting ability. A mobile robot's CC preferably resides in a well-controlled range in order to negotiate a wide array of obstacles. Further, a typical vehicle with a fixed CG would need to have its CG near ground level and near the center of the track footprint. This, unfortunately, is difficult to achieve since it is difficult to design any “practical” system with the CG so far offset from its volume centroid (most of the volume would need to remain vacant). This is especially true when ground clearance will need to be allotted on the bottom of the chassis.

The alternative to having a fixed CG is having some type of “CG shifting” capability such as that illustrated in <figref idrefs="DRAWINGS">FIG. 9</figref>. This means that the vehicle CG can be relocated as necessary to negotiate obstacles. In the illustrated example, the flippers <b>802</b> do allow for some CG shifting since they can be rotated in any direction and can be designed to contain some percentage of the total weight of robot <b>800</b>. However, since the flippers need to be in a defined position for many obstacles (and therefore cannot be rotated at will), this limits their ability to contribute adequate CG shifting ability. In contrast, the robot will often be required to have a head that can be elevated via a neck that typically has few constraints regarding its position while scaling obstacles (other than to give a remote operator ample viewing of the surroundings).

The depicted robot <b>800</b> in <figref idrefs="DRAWINGS">FIG. 9</figref> has a neck <b>805</b> that is a single, rigid link. However, some embodiments may have necks with multiple links and articulating joints or “elbows.” Neck <b>805</b> is illustrated in five different positions to illustrate its range of movement. Since the head is often required for scanning ability to have a high reach such as, for example, at least 20 inches off of the ground, neck <b>805</b> is preferably as long as possible while still stowable atop the robot <b>801</b> (represented by black outline in <figref idrefs="DRAWINGS">FIG. 9</figref>). Having such a long neck <b>805</b>, means that the head <b>803</b> does not need to be a very large percentage of the robot weight (without payload) to result in fairly large CG shifts for the vehicle. In fact, the depiction above represents having only about 15%, of the robot weight in the head, and another 5% in the neck itself. A longer neck is preferred for better leverage, so some robots have jointed necks or necks extending, in stowed positions, beyond the end of the chassis.

<figref idrefs="DRAWINGS">FIG. 9</figref> depicts various target dots toward the center, each corresponding to a combined robot center of gravity for one position of the head. The depicted range of movement is exemplary, and other ranges of movement may be achieved by placing neck <b>805</b> in other locations or changing the shape and design of heck <b>805</b>, for example. Depicted position P<b>1</b> produces a combined CG at the location marked CG<b>1</b>, thus lowering and moving forward the combined CG relative to most other positions. Depicted position P<b>2</b> produces a combined CG at the location marked CG<b>2</b>, which is higher than CG<b>1</b> and forward of most other positions. Depicted position P<b>3</b> produces a combined CG at the location marked CG<b>3</b>, this is the highest depicted CG Depicted position P<b>4</b> produces a combined CG at the location marked CG<b>4</b>. Depicted position P<b>5</b> is a stowed position, and produces a combined CG at the location marked CG<b>5</b>, thus lowering and moving forward the combined CG relative to most other positions. There are labeled dots also toward the center of the P<b>4</b> bead and neck, as well as the flippers <b>802</b> and the chassis <b>801</b>. These represent the individual component center of gravity for that piece. Movement of the centers of gravity of the head <b>803</b>, neck <b>805</b>, and flippers <b>802</b> effect the changes in combined CG position as described herein.

The depicted CG locations depend, of course, on the orientation of the vehicle. Climbing orientations with the chassis oriented at a pitch will of course have different CG locations, but the general CG shifting effect is exemplified in this drawing. CG locations also depend on flipper location and the relative weight of the flippers <b>802</b> to the rest of robot <b>800</b>.

In the depicted embodiment, though not visible in this side representation, neck <b>805</b> is preferably adapted to move centrally between flippers <b>802</b> such that the flippers do not interfere with neck movement. Other positions may be used.

Note that the neck could be reversed from what is depicted above such that it pivots from the rear of the vehicle. This would shift the centroid of the CG range aft, which can be advantageous if more weight is packaged in the flippers.

While CG shifting directed along the front/rear axis is depicted, CG shifting as described herein may of course be accomplished in other directions, such as sideways, or downward. For example, a robot navigating a slope with a sideways slant may benefit from sideways or diagonal CG shifting. Such shifting may be accomplished using various head/neck joint morphologies described herein.

<figref idrefs="DRAWINGS">FIG. 10</figref> depicts elevated neck positions for two configurations. The location of the neck pivot, whether mounted at the front or rear of the chassis, affects how high the head can be elevated off the ground for surveillance. In both cases, the flippers can be used to elevate the head by either using “prairie-dog” (drive on flipper tracks only) or “bulldog” (run on the flipper tips and main tracks) poses. The former results in a higher head position as shown in <figref idrefs="DRAWINGS">FIG. 10</figref>.

Furthermore, it is possible to “combine” the chassis and the neck as a single entity, and have dual flippers on one end of the vehicle. In this case, the vehicle always rides on one or both sets of lightweight flippers, and the heavy neck can be pivoted about the front axle to supply the weight shifting ability. This concept requires longer flippers to effectively climb stairs, but has the benefit of having most of its weight concentrated in the neck to achieve large CG shifts. The head (which would be at the end of the neck) could be elevated by standing on the flipper tips to achieve the required height. This example is described in a copending Patent Application No. 60/828,606, filed Oct. 6, 2006, and entitled “Robotic Vehicle.”

<figref idrefs="DRAWINGS">FIG. 11</figref> depicts a robot <b>1100</b> in various positions crossing a crevasse. In operation, robot <b>1100</b> approaches the crevasse a (<figref idrefs="DRAWINGS">FIG. 11</figref><i>a</i>) with neck <b>305</b> in a declined position that shifts the weight of the head and neck to move the robot's combined center of gravity (combined CG) to the spot marked CG<b>6</b>. In this configuration, robot <b>1100</b> may move straight toward crevasse A and roll forward until the front flipper contacts the opposing side of the crevasse. Because CG<b>6</b> is never over the crevasse before the leading flipper edge is supported, robot <b>1100</b> does not fall.

After reaching the position shown in <figref idrefs="DRAWINGS">FIG. 11A</figref>, the robot pivots neck <b>305</b> to the second position depicted in <figref idrefs="DRAWINGS">FIG. 11B</figref>. In this position, the robot combined CG is at the point marked CG<b>7</b>, which is over the chassis portions that are supported, and thereby robot <b>1100</b> may move forward and complete the crevasse crossing without the trailing end falling into the crevasse. In a preferred embodiment, the robot can traverse from positions <b>11</b>A to <b>11</b>B at the same time neck is moving to shift the robot CG, as long as neck gets to position <b>11</b>B before robot does.

As shown, there are two distinct crevice dimensions, “A” and “B,” dictated by the location of the vehicle's CG relative to both of its outermost axles. Since any vehicle crossing a crevice must pass through both of these extremes, the maximum crevice that a vehicle can cross is always the smaller of “A” or “B.” Note that for a typical vehicle with a fixed CG location, the sum of A and B is always the total length of the track span. Therefore, the maximum crevice that a fixed-CG vehicle can cross can be no larger than half of the track span, and the CG must reside in the middle of the track footprint to do so. However, if the vehicle is capable of shifting its CG fore and aft, it is possible to cross much larger crevices. In this case, the maximum crevice is still the smaller of A or B, but the sum and A and B is now equal to: <br /><i>A+B</i>=Track Span+<i>CG </i>Shift

Since the maximum crevice would be when A=B, this gives: <br />Maximum Crevice=(Track Span+<i>CG </i>Shift)/2

Therefore, the crevice size can be increased by half of whatever CG shifting ability can be achieved, but the vehicle's “average” CG should still be in the middle of the track span or this gain is lost.

<figref idrefs="DRAWINGS">FIG. 12</figref> depicts another robot CG shifting technique. Climbing stairs becomes very difficult as vehicle size decreases. It is desired that the vehicle be stable at any point during climbing to allow stopping and starting at any time and consistent performance at various speeds. To climb stairs stably, the vehicle CG must always be supported between two step edges. This means that as the CG traverses over the edge of a step, the vehicle must be at least long enough to simultaneously span from the next step edge to the previous step edge as shown below in <figref idrefs="DRAWINGS">FIG. 12</figref>. This means that the total track footprint (the entire length of track in contact with the ground) must be at least two “step diagonals” long.

The depicted robot <b>1200</b> in <figref idrefs="DRAWINGS">FIG. 12</figref> has neck <b>305</b> deployed in a stair ascending position. Such position requires neck <b>305</b> to be pivoted forward such that the head and neck center of gravities are in front of the chassis. This provides, in the depicted scenario, a robot combined CG located at the point marked CG<b>9</b>. Because this point is in front of the chassis contact with the middle stair when the rearmost chassis contact leaves the lower stair (forward motion), robot <b>1200</b> is stabilized. Some embodiments of robots may be so small that forward stair climbing is not possible without such CG shifting. For example, a small robot may have a combined CG at the point CG<b>8</b>, which would not provide stable climbing because the rear end of the robot would sink along the lower step as forward progress is made, possibly even flipping over backwards. Such a robot, equipped with a head and neck as described herein, may shift its CG up to position CG<b>9</b> for example, and climb successfully.

<figref idrefs="DRAWINGS">FIG. 13</figref> is a flow chart of a method of ascending an obstacle. The method is preferably employed with small robots having a neck and head as included herein, but may also be employed with larger robots or other vehicles. In Step <b>1301</b>, the vehicle approaches the obstacle traveling forward and raises flippers (flippers are “front”). In step <b>1302</b>, the vehicle mounts the obstacle preferably using its drive and flipper tracks, to a position where the vehicle combined CG is either over the top edge of the obstacle or may be positioned there by CG adjustment. In step <b>1303</b>, the vehicle pivots its neck to move the CG forward (toward direction of motion) and preferably downward. In step <b>1304</b>, flippers and drives are then used to complete the ascension. Various robots may be remotely controlled to perform the various navigational functions described herein, or they may be controlled by a programmed controller, preferably housed on the robot. A combination of such control methods may also be used.

<figref idrefs="DRAWINGS">FIG. 14</figref> shows a robot <b>1400</b> having a wheel drive <b>1401</b>. Wheels <b>1401</b> may be overlapped to provide track-like maneuvering capability. They may also be provided with independent suspension. Wheels <b>1401</b> may be commonly driven or independently driven. Robot <b>1400</b> may also perform the various CG shifting functions described herein.

<figref idrefs="DRAWINGS">FIG. 15</figref> depicts a robot in a stowed configuration. Neck <b>303</b> and head <b>305</b> are stowed within the dimensions of chassis <b>301</b>. Flippers <b>302</b> are also pivoted back and stowed within the chassis <b>301</b>. This configuration provides a stowed length equal to the marked chassis length CL. That is, flipper length FL, neck length NL, and head length HL do not add to the combined length of the robot in this stowed position. Further, the flippers, head, and neck in stowed position do not extend beyond the chassis height marked CH (or beyond the chassis width.) Ones preferred robot design uses a CL of less than 24.5″, a CH of less than 7.5″, and a chassis width of less than 16″.

<figref idrefs="DRAWINGS">FIG. 16</figref> depicts a perspective view of another robot vehicle. <figref idrefs="DRAWINGS">FIG. 17</figref> depicts the robot of <figref idrefs="DRAWINGS">FIG. 16</figref> in a climbing configuration. Referring to <figref idrefs="DRAWINGS">FIGS. 16 and 17</figref>, the depicted robot vehicle has a chassis <b>1601</b> linked to a track drive comprising wheels <b>1606</b> and track <b>1610</b>. The front of robot <b>1600</b> is provide with flippers <b>1602</b> having tracks driven by wheels <b>1600</b>, which are linked to drive motors mounted on chassis <b>1601</b>. The drive is preferably powered by power source <b>1608</b>, which may be a battery, or other power source mounted to chassis <b>1601</b>. The drive wheels may be constructed according to techniques taught in U.S. Pat. No. 6,615,885, which has been incorporated by reference herein.

The depicted robot <b>1600</b> has an articulated neck <b>1605</b>, which may orient head <b>1603</b> in various positions. <figref idrefs="DRAWINGS">FIG. 16</figref> shows a typical maneuvering position with the neck angled backward, moving the combined center of gravity of robot further toward the rear end. This position may also allow viewing of flippers <b>1602</b> through visual sensors <b>1604</b>. Logic rollers <b>1607</b> support track <b>1610</b>. Such rollers may be in a single line or may be staggered to provide more constant support for a track as it moves along a stair edge, for example.

<figref idrefs="DRAWINGS">FIG. 17</figref> depicts robot <b>1600</b> in a position that may improve climbing capability. Flippers <b>1602</b> are deployed at a straight angle with the bottom of the chassis track drive. Neck <b>1605</b> is pivoted forward to move head <b>1603</b> in front of the vehicle and thereby shift forward the vehicle combined CG as described herein. Head <b>1603</b> is depicted rotated upon the final articulated portion of neck <b>1605</b>, which may be employed to direct sensors <b>1604</b> to varied directions. The depicted angle of neck <b>1605</b> is exemplary, and neck <b>1605</b> may be deployed at various angles including below the angle of flippers <b>1602</b> in some implementations.

<figref idrefs="DRAWINGS">FIG. 18</figref> depicts another robot in a stair climbing position with a forward-shifted combined CG. The depicted robot has chassis <b>801</b> having a chassis CG marked toward its center. The robot is climbing a stairway. Flippers <b>802</b> are pivoted in a forward position along the stairway, having their lower track aligned with the bottom of the main drive track of chassis <b>801</b>. The combined CG is depicted as a large target dot. This combined CG location is produced by orienting the flippers (having the depicted flipper CG) as indicated and by moving neck <b>805</b> (having the depicted neck CG) with head <b>803</b> (having the depicted head CG). The CG positioned at this point allows smoother climbing as the rearmost track crests the depicted rearmost stair edge. The head is pivoted upward to allow sensors to view directly up the stairs.

<figref idrefs="DRAWINGS">FIG. 19</figref> depicts another robot in a stair descending position. In this configuration the robot has chassis <b>801</b> pointing downward. Neck <b>805</b> is pivoted back to move the combined CG (marked as “Combined CG”) to its position above the central depicted stair edge. Head <b>803</b> is pivoted downward to view the path in front of the robot.

<figref idrefs="DRAWINGS">FIG. 20</figref> depicts a robot climbing an obstacle forward. The depicted robot employs its flipper <b>802</b> track drives and chassis <b>801</b> drive to crest the obstacle, then pivots forward flippers <b>802</b> and neck <b>805</b>. Such movement shifts component weight to provide a combined CG at the depicted point above the crest of the obstacle, which allows forward movement of the total robot mass on top of the obstacle.

<figref idrefs="DRAWINGS">FIG. 21</figref> shows a robot mounting an obstacle backwards. The depicted robot preferably approaches the obstacle in a manner depicted in <figref idrefs="DRAWINGS">FIG. 8</figref>. Neck <b>805</b> and head <b>803</b> are then stowed to move the combined CG lower and toward the desired direction of movement. This technique preferably places the combined CG above the crest of the obstacle as indicated and makes forward movement possible up the obstacle.

<figref idrefs="DRAWINGS">FIG. 22</figref> depicts a cutaway perspective view of a robot <b>2200</b> according to another embodiment. The view highlights the morphology of moving joints along the robot's neck extension and sensor head. Each depicted axis allows for pivotal or panning movement about the central axis arrows depicted for illustration only. Robot <b>2200</b> includes generally a right track assembly <b>2202</b>, a left track assembly <b>2204</b>, and a head <b>2206</b>, which are illustrated in dotted lines to show their position relative to the depicted actuated joints or axes.

Specifically, the depicted robot also includes a shoulder axis or actuated joint <b>2208</b>, a neck <b>2210</b>, a first tilt axis or actuated joint <b>2212</b>, a pan axis or actuated joint <b>2214</b>, and a second tilt axis or actuated joint <b>2216</b>. Each depicted axis allows for pivotal or panning movement about the central axis arrows depicted for illustration only. The depicted axes are actuated joints moveable by robotic actuators coupled thereto. A preferred joint or axis design includes an actuator module with a motor, a motor driver, and digital logic for motor control. Axes employed herein may have variations, of size, actuator power, and other parameters based on design considerations. For example, shoulder actuated joint or axis <b>2208</b> may be more powerful than the other depicted axes in some designs because of neck/head weight. Appropriate gears may also couple the actuators to the attached moveable joints. One preferred actuator design scheme is further described below, but any suitable actuators may be used.

Shoulder axis <b>2208</b> is mounted toward one end of the robot <b>2200</b> and is used to elevate the neck <b>2210</b>. Preferably, actuated joint <b>2208</b> has a movement range limited only by the chassis of robot <b>2200</b>. The movement range thereby extends below parallel toward both ends of robot <b>2200</b> in a preferred design. Preferred actuator circuitry is further described below. Toward the distal end of neck <b>2210</b>, is first tilt axis <b>2212</b>. Tilt axis <b>2212</b> is, in this embodiment, parallel to shoulder axis <b>2208</b>. Connected to one side of tilt axis <b>2212</b> is pan axis <b>2214</b>, which is used for panning the head. Connected along the top of pan axis <b>2214</b> is the second tilt axis <b>2216</b>. The depicted sensor head <b>2206</b> is fixed to the top of tilt axis <b>2216</b>. Preferably, neck <b>2210</b> is constructed to provide a large range of movement at each of the depicted axes.

<figref idrefs="DRAWINGS">FIG. 23</figref> illustrates a cutaway perspective view of another robot <b>2300</b>. The depicted view highlights the different neck-head axis topology. Each depicted axis allows for pivotal or panning movement about the central axis arrows depicted for illustration only. In this embodiment, the robot <b>2300</b> comprises right track assembly <b>2202</b>, left track assembly <b>2204</b>, and head <b>2206</b>. Robot <b>2300</b> also comprises shoulder axis <b>2208</b>, neck <b>2210</b>, and first tilt axis <b>2212</b>. The first tilt axis <b>2212</b> is attached to a pan link <b>2302</b>. The pan link is also attached to the second tilt axis <b>2216</b>, and the second tilt axis <b>2216</b> is movably coupled to the head <b>2206</b>. The pan link <b>2302</b> in general is an assembly with a panning axis and one or more extended pieces which may include bends. A pan link may be packaged into an assembly including a first piece perpendicular to neck <b>2210</b>, an actuator, and a second piece pivotable in a plane approximately parallel to neck <b>2210</b>. (A preferred pan axis is further described below). The depicted axes or “joints” are preferably implemented with actuators constructed as described herein. Various embodiments may employ different configurations to implement axes or joints depicted herein. As will be described further below, the pan link may be constructed with a height, that is approximately equivalent to the height of a single actuator.

<figref idrefs="DRAWINGS">FIG. 24</figref> depicts a cutaway perspective view of a robot <b>2500</b> according to another embodiment. Each depicted axis allows for pivotal or panning movement about the central axis arrows depicted for illustration only. The depicted axes are preferably implemented with actuators constructed as described herein. In this embodiment, robot <b>2500</b> comprises right track assembly <b>2202</b>, left track assembly <b>2204</b>, and head <b>2206</b>. Robot <b>2500</b> in this embodiment also includes shoulder axis <b>2208</b>, neck <b>2210</b>, first tilt axis <b>2212</b>, and tilt axis <b>2214</b>. First tilt axis <b>2212</b> is movably attached to tilt axis <b>2214</b>, which is directly attached to head <b>2206</b>. Panning capability provides the fourth degree of freedom of movement, and is enabled by twist joint <b>2502</b>. An actuator providing joint movement for twist joint <b>2502</b> may be provided in the interior of neck <b>2210</b> or mounted to the exterior. This variation provides four degrees of freedom for movement while positioning three axes or actuated “joints” with a short lever arm to move sensor head <b>2206</b>.

<figref idrefs="DRAWINGS">FIG. 25</figref> depicts another example of a robot <b>2500</b> in a perspective view. Each depicted axis allows for pivotal or panning movement about the central axis arrows depicted for illustration only. The depicted axes are preferably implemented with actuators constructed as described herein. In this embodiment, robot <b>2600</b> includes right track assembly <b>2202</b>, left track assembly <b>2204</b>, and head <b>2206</b>. Robot <b>2500</b> also comprises shoulder axis <b>2208</b>, neck <b>2210</b>, first tilt axis <b>2212</b>, and pan axis <b>2214</b>. In this embodiment, first tilt axis <b>2212</b> is mounted toward the distal end of neck <b>2210</b>. A second tilt axis <b>2602</b> is connected to one side of tilt axis <b>2212</b>. Tilt axis <b>2602</b> is connected to a piece of tilt axis <b>2212</b> that is moveable with respect to neck <b>2210</b>, and the second tilt axis is similarly coupled to the pan axis <b>2214</b> to allow panning movement of head <b>2206</b>.

<figref idrefs="DRAWINGS">FIG. 26</figref> depicts a perspective view of a robot <b>2600</b> according to another embodiment. Each depicted axis allows for pivotal or panning movement about the central axis arrows depicted for illustration only. The depicted axes or “joints” are, preferably implemented with actuators constructed as described herein. In this embodiment, robot <b>2600</b> includes right track assembly <b>2202</b>, left track assembly <b>2204</b>, and head <b>2206</b>. Robot <b>2600</b> also includes shoulder axis <b>2208</b>, neck <b>2210</b>, and first tilt axis <b>2212</b> mounted toward the distal end of neck <b>2210</b>. First tilt axis <b>2212</b> is movably coupled by the actuator tilt action to a 45-degree link section <b>2702</b>. The 45-degree link section <b>2702</b> may be capable of rotational motion about its length. Pan axis <b>2214</b> is fixed at the distal end of link section <b>2702</b>, and head <b>2206</b> is thereby moveably mounted to the top of pan axis <b>2214</b>.

<figref idrefs="DRAWINGS">FIG. 27</figref> illustrates a possible configuration of a preferred design for a neck extension and actuator assembly <b>4300</b> (“assembly <b>4300</b>”) having a pan axis. Assembly <b>4300</b> comprises a shoulder actuated joint <b>4302</b>, a neck <b>4304</b>, a first actuated tilt joint <b>4306</b>, a actuated pan link <b>4308</b>, and a second actuated tilt joint <b>4310</b>. The robot's sensor head is meant to be mounted atop the actuated tilt joint <b>4310</b>. The depicted pan link design is a presently preferred embodiment of a pan link (<figref idrefs="DRAWINGS">FIG. 23</figref>). Shoulder actuated joint <b>4302</b> is coupled to neck <b>4304</b>, and neck <b>4304</b> is coupled to first actuated tilt joint <b>4306</b>. First actuated tilt joint <b>4306</b> is movably coupled to pan link <b>4308</b>. Pan link <b>4308</b> in this configuration is movably coupled to actuated tilt joint <b>4310</b>, and is capable of panning the actuated tilt joint <b>4310</b>. The depicted axes are preferably implemented with actuators constructed as described herein.

Actuated pan link <b>4308</b> provides further degrees of freedom head movement over other embodiments described herein with less than four degrees of freedom. The center of gravity shifting (CG shifting) techniques described herein may also be enhanced with use of pan link <b>4308</b>. Specifically, the pan link may be pivoted or extended, backward to achieve maximum rearward CG shifting described herein for tasks such as the beginning phases of an obstacle climb. Similarly, actuated pan link <b>4308</b> may be pivoted forward and the head tilted down to achieve maximum forward-down CG, shifting for tasks such as stair ascending and completing a large obstacle ascension, for example.

<figref idrefs="DRAWINGS">FIG. 28</figref> illustrates a cutaway view of a possible embodiment of a robotic actuator assembly <b>4400</b> of <figref idrefs="DRAWINGS">FIG. 27</figref>. In this view, some of the outer housings have been removed in order to reveal that the assembly <b>4400</b> includes a shoulder axis actuator <b>4402</b>, a first tilt axis actuator <b>4406</b>, a pan link actuator <b>4408</b>, and a second tilt axis actuator <b>4410</b>. In this view, it can also be seen that the assembly <b>4400</b> also includes a shoulder axis circuit board <b>4412</b>, a neck circuit board <b>4414</b>, a first tilt axis circuit board <b>4416</b>, a pan link circuit board <b>4418</b>, and a second tilt axis circuit board <b>4420</b>. Each the circuit boards <b>4412</b> through <b>4420</b> provide the circuit connectivity, power regulation, motion control, sensors, and other functions related to each axis, and the circuit boards <b>4412</b> through <b>4420</b> may be rigid circuit boards, flexible polyimide circuits, or other circuit modules or combinations thereof.

<figref idrefs="DRAWINGS">FIG. 29</figref> depicts a cutaway view of a possible embodiment of a first tilt axis <b>4500</b>. In this view, the outer housing of the axis <b>4500</b> has been removed to reveal internal components that include circuit boards <b>4502</b>, a motor <b>4504</b>, a ring gear <b>4506</b>, a pinion gear <b>4508</b>, a output gear <b>4510</b>, and a slip ring <b>4512</b>. Circuit boards <b>4502</b> and slip ring <b>4512</b> may be rigid circuit boards, flexible polyimide circuits, or other circuit modules or combinations thereof, and may provide power regulation, motion control, sensors, and other functions related to the axis <b>4500</b>. Motor <b>4504</b> is coupled to ring gear <b>4506</b>, and ring gear <b>4506</b> is mechanically linked to pinion gear <b>4508</b> via a collection of planetary gears (hidden in this view). Ring gear <b>4506</b>, pinion gear <b>4508</b>, and the hidden planetary gears form a “planetary” gear system which transfers power from the motor <b>4504</b> to the output gear <b>4510</b> and provides a gear ratio. Slip ring <b>4512</b> provides electrical connections that may conduct power, communications, and other signals.

<figref idrefs="DRAWINGS">FIG. 30</figref> depicts another cutaway view of a possible embodiment of a first tilt axis <b>4600</b>. In this view, the outer housing and ring gear have been removed. In this view, circuit boards <b>4502</b>, motor <b>4504</b>, pinion gear <b>4508</b>, output gear <b>4510</b>, and slip ring <b>4512</b> are all visible. In this view, it can be seen that axis <b>4600</b> also includes a slip clutch <b>4602</b> and a collection of planet gear assemblies <b>4604</b>. The depicted slip clutch <b>4602</b> may help mitigate damage to the gears from outside pressure rotating the robot neck, for example. One preferred slip clutch design slips at about 400 inch-pounds of force. Other slip clutches may be used. The depicted motor actuator assembly is preferably backdriveable. Referring again to the actuated joints depicted in <figref idrefs="DRAWINGS">FIG. 27</figref>, actuated tilt joint <b>4306</b>, actuated pan joint <b>4308</b>, an actuated tilt joint <b>4310</b>, each employ backdriveable actuator motor in preferred embodiments. Preferably, the actuator modules employed in these three actuated joints are interchangeable. That is the modules employed his same motor, geared slip clutch, and gear electronics. In a preferred embodiment the actuated shoulder joint <b>4302</b> is non-backdriveable.

<figref idrefs="DRAWINGS">FIG. 31</figref> depicts a cutaway view of a possible embodiment of a first tilt axis <b>4700</b>. This view has the outer housing and ring gear removed and depicts circuit boards <b>4502</b>, motor <b>4504</b>, pinion gear <b>4508</b>, and planet gear assemblies <b>4604</b>. This view also has the slip clutch housing removed to reveal the clutch pack <b>4702</b>. The clutch pack includes a collection of clutch wafers and springs. While one slip clutch embodiment is disclosed, other suitable clutches may be employed depending on size, actuator design, performance requirements, and other design constraints.

<figref idrefs="DRAWINGS">FIG. 32</figref> illustrates a cutaway view of a possible embodiment of a second tilt axis <b>4800</b>. This assembly includes an outer housing (removed in this view), a ring gear (removed in this view), a motor <b>4802</b>, a collection of planet gears <b>4804</b>, a clutch pack <b>4806</b>, and a sun gear <b>4808</b>. The axis <b>4800</b> also includes a slip ring <b>4810</b>, and in this view half of the slip ring has been hidden in order to reveal a collection of electrical contacts <b>4812</b> that may conduct power, communications, and other signals from the visible half of slip ring <b>4810</b> to the hidden half. Circuit boards <b>4810</b> and <b>4814</b> may be rigid circuit boards, flexible polyimide circuits, or other circuit modules or combinations thereof, and may provide power regulation, motion control, sensors, and other functions related to the axis <b>4800</b>.

<figref idrefs="DRAWINGS">FIG. 33</figref> illustrates a cutaway view of a possible embodiment of a neck attachment or “shoulder” axis <b>4900</b>. Various components have been hidden in this, view in order to reveal that the neck axis <b>4900</b> includes a slip ring <b>4902</b>. In this view, half of the slip ring has been hidden to reveal that the slip ring includes a collection of electrical contacts <b>4904</b> that may conduct power, communications, and other signals from the hidden half to the visible half of slip ring <b>4902</b>. Neck axis <b>4900</b> also includes a spring <b>4906</b> mounted behind the slip ring <b>4902</b>. This spring <b>4906</b> may allow the slip ring to float, and this may allow the axis <b>4900</b> to be constructed using greater mechanical tolerances than may otherwise be allowed.

<figref idrefs="DRAWINGS">FIG. 34</figref> depicts another cutaway view of a possible embodiment of a neck axis <b>5000</b>. Various components have been hidden in this view in order to reveal that the neck axis <b>5000</b> includes a first slip ring half <b>5002</b>, a second slip ring half <b>5004</b>, and a collection of electrical contacts <b>5006</b>. Contacts <b>5006</b> maintain electrical contact with a collection of concentric electrical traces <b>5008</b>. Slip ring components <b>5002</b> through <b>5008</b> may be used to conduct power, communications, and other signals. First slip ring half <b>5002</b> and second slip ring half <b>5004</b> may be constructed such that when the neck axis <b>5000</b> is disassembled, the halves <b>5002</b> and <b>5004</b> separate. Such construction preferably allows a wire free connection of robot neck and head. In certain embodiments, the first slip ring half <b>5002</b> and second slip ring half may be used as an absolute encoder pair.

<figref idrefs="DRAWINGS">FIG. 35A</figref> and <figref idrefs="DRAWINGS">FIG. 35B</figref> show two exploded perspective views of a neck extension connector according to one embodiment. The depicted connector base <b>3502</b> is preferably mounted to chassis <b>301</b> on an interior-facing surface such as an inside surface of the drive housing as depicted in several examples herein. The connector may of course be mounted in other positions such as a centrally located post or on an outer-facing surface. The inner surface is preferred. Connector base <b>3502</b> is provided with threads preferably arranged to provide a quarter-turn screw-on sequence for neck <b>3304</b>. Base <b>3502</b> may be milled, machined, molded, or manufactured with other suitable techniques. A preferred embodiment is molded high-strength plastic, but other materials such as metals may be used. In a preferred embodiment connector base <b>35</b> at two is an engaging mount that has few threads. The threads have a very large pitch, and open angle, and preferably no thread completes much more than a quarter perimeter. While quarter turn threads are taught, this is not limiting and other thread arrangements may be used. Preferably movement with less than half a rotation may assemble the opposing pieces of the connector. Interruptions may be provided along the perimeter between threads.

The neck connector piece <b>3512</b> is preferably a metal piece with interior threads adapted to screw onto the outer threads of base <b>3502</b>. In some embodiments, connection may be made with a quarter turn engagement. That is, the neck or payload may be attached with a twist to engage the threads on the base <b>3502</b> without a friction or interference fit. Such a connection is secured with the use of a latch or other securing piece. Electrical contact pads <b>3504</b> are expressed on a circuit board which is fitted into base <b>3502</b>. Contacts <b>3504</b> match to corresponding electrical contacts <b>3522</b> (<figref idrefs="DRAWINGS">FIG. 35B</figref>) present inside the neck connector piece. Contacts <b>3522</b> are clocked to screw on and align with contacts <b>3504</b>. Electrical connection is made through base <b>35</b> through pins projecting from the back of base <b>3502</b> to provide electrical conductivity into the chassis circuitry.

Referring to <figref idrefs="DRAWINGS">FIG. 35B</figref>, neck connector piece <b>3512</b> is attached to neck <b>3304</b> via screwing or welding or other suitable technique, or neck connector piece <b>3512</b> may be machined as part of the neck housing of neck <b>3304</b>. Neck connector piece <b>3512</b> has interior threads <b>3513</b>. Behind threads <b>3513</b> is a sealing o-ring or seal ring <b>35118</b>. Seal ring <b>3518</b> preferably forms a seal against base <b>3502</b> in the connector closed position. Behind the seal ring <b>3518</b> is a small circuit board <b>3520</b> fit into neck connector piece <b>3512</b>. Preferably circuit board <b>3520</b> is sealed with a second o-ring <b>3524</b>. Contacts <b>3522</b> are, in this embodiment, mounted to circuit board <b>3520</b>.

A latch <b>3506</b> is used to latch the depicted connector arrangement in a closed position. Latch <b>3506</b> is shown with plunger <b>3508</b> spring loaded therein. Plunger <b>3508</b> may be screwed into latch <b>3506</b> to adjust the latch closing force. In preferred scenario the closing forces is adjusted similarly to a vice grips. That is plunger <b>3508</b> is screwed into latch <b>3506</b> and the closing force tested until the latch can no longer be closed. Then plunger <b>3508</b> is screwed out slightly to allow the latch to close at its maximum closing force position. Such position provides, in preferred embodiments, a zero-backlash connection. Latch <b>3506</b> is rotatably mounted to a latch base <b>3516</b> which in one embodiment is screw-mounted to the chassis. In another embodiment the latch base may be mounted to neck connector piece <b>3512</b>.

<figref idrefs="DRAWINGS">FIG. 35C</figref> depicts the neck extension connector latched and secured. The view is shown from the robot chassis side, with the robot chassis not shown in this cutaway view for clarity. After connection, the depicted connector arrangement is secured by latch <b>3506</b>. A plunger or screw <b>3508</b> is moved into a matching hole or receiving slot <b>3526</b> on neck connector piece <b>3512</b> to secure the neck to the chassis. Such an arrangement provides a mounting scenario with no tools, wires or screws, and provides an adjustable latch which allows for different types of payloads to be mounted to connector <b>3502</b>.

The depicted latch in a closed position provides a zero backlash connection in that, once latched, the depicted neck connector has no freedom of movement. The assembly may be referred to as a quick-connect zero backlash connector. Other suitable connector designs may be employed to provide a quick connect zero backlash capability. The plunger must be pulled out of receiving slot <b>3526</b> in order to disconnect the connector. The unlatching movement is accomplished by pushing upward on the head end of plunger <b>3508</b>, thereby rotating latch base <b>3516</b> upward about screw <b>3528</b>, while at the same time rotating the tip of plunger <b>3508</b> downward along the surface of neck connector piece <b>3512</b> until contact is cleared. Assembly and disassembly are preferably accomplished with a single quarter turn movement and a latching or unlatching movement.

While the depicted connector is shown holding the robot neck assembly <b>3304</b> onto the robot chassis however such a connector may be used as a payload connector to quick connect a variety of payloads to a robot chassis, or quick connect other robot pieces together while providing a sealed housing and electrical connection as well as a zero backlash mechanical connection. Various payloads may be connected. For example a cargo platform, or a manipulator arm may be connected. Various sensing payloads or weapons payloads may also be connected.

<figref idrefs="DRAWINGS">FIG. 36</figref> is a block diagram <b>28000</b> of one possible embodiment of a robot head <b>28002</b> (“head”, “robot head,” “sensor head”). The head <b>28002</b> includes a head housing <b>28002</b> in which is mounted one or more circuit boards or circuit modules. Rigid circuit boards, flexible polyimide circuits, multi-chip modules, or other circuit modules or combinations may be used. The depicted head <b>28002</b> has various cameras, sensors, and antenna mounted therein or thereto, and is typically itself mounted to a robot neck extension such as those described herein.

In this embodiment head <b>28002</b> includes a single board computer (SBC) <b>28100</b>, and in a preferred embodiment the SBC <b>28100</b> is a Freescale MPC5200. Further, in one preferred embodiment the SBC is the controller for the entire robot. SBC <b>28100</b> is connected to a global positioning system (GPS) module <b>28102</b> by a serial bus, and in a preferred embodiment the GPS <b>28102</b> is a uBlox Super Sense GPS module. The GPS module is also connected to a GPS antenna <b>28108</b>. The SBC <b>28100</b> also uses a PCI bus to connect to a wireless Ethernet transceiver <b>28104</b> and a field-programmable gate array (FPGA) <b>28200</b>. In a preferred embodiment, the FPGA <b>28200</b> is a Xilinx XC3S1000. SBC <b>28100</b> is electronically connected to a first bus buffer <b>28105</b>, which in a preferred embodiment is a Linear Technology LTC4304, which is connected to a PMBus <b>28604</b>. A microcontroller power module <b>28106</b>, which receives power from VSTBY power <b>28107</b>, is also connected to PMBus <b>28604</b> by a second bus buffer <b>28108</b>.

Referring now to the centrally depicted FPGA in <figref idrefs="DRAWINGS">FIG. 36</figref>, FPGA <b>28200</b> is provided in robot head <b>28002</b> to perform various digital logic and data routing functions such as multiplexing the video or sensor signals to appropriate destinations, as well as, in this embodiment, interfacing to an actuator data communications bus known as FARnet. FPGA <b>28200</b> is electronically connected to control an LED power supply <b>28202</b>, which supplies power to an infrared LED array <b>28204</b>. FPGA <b>28200</b> is electronically connected to a pair of RS485 transceivers <b>28206</b> and <b>28208</b>, and the transceivers <b>28206</b> and <b>28208</b> are connected to a four-conductor FARnet bus <b>28602</b>. FPGA <b>28200</b> is also electronically connected to a digital signal processor (DSP) <b>28400</b>, which processes audio signals that may be input from microphones or output to speakers. In one preferred embodiment, the DSP <b>28400</b> is a Texas Instruments TMS320DM642. DSP <b>28400</b> is electronically connected to an electronic memory <b>28402</b>, which may be RAM, SDRAM, flash, etc., or may be connected to any combination of one or more of such types of memory. Preferably a combination of flash memory and SDRAM is employed for program and data storage, and operating memory. DSP <b>28400</b> is electronically connected to an audio codec <b>28404</b>, which in a preferred embodiment is a Texas Instruments' TLV320AIC23, and the audio codec <b>28404</b> is connected to an audio line input <b>28406</b>, a microphone input <b>28408</b>, a line output <b>28410</b> and an amplifier <b>28412</b>.

The head <b>28000</b> also includes an electro-optic infrared (EOIR) module <b>28900</b>. EOIR <b>28900</b> includes a near infrared (NIR) camera <b>28902</b> (in a preferred embodiment, Sony 980), a long wave infrared (LWIR) camera and a laser range finder <b>28906</b>. The EOIR cameras <b>28902</b> and <b>28904</b> are connected to a pair of video decoders <b>28912</b> and <b>28914</b> (in a preferred embodiment, Analog Devices ADV7180). Laser range finder <b>28906</b> is connected to a digital video input <b>28916</b>. The video decoders <b>28912</b> and <b>28914</b>, the digital video input <b>28916</b>, as well as a drive camera <b>28908</b> are connected to FPGA <b>28200</b> by a CCIR-656 video communications bus and a serial bus. Video decoder <b>28914</b> is also connected to a differential NSTC receiver <b>28918</b>.

The depicted head <b>28000</b> also includes an Ethernet switch <b>28300</b> (in a preferred embodiment, Marvell 88E6063) which connects the SBC <b>28100</b> to a head payload connector <b>28700</b>, a head connector <b>28600</b> providing connectivity to the robot base, and a local area network (LAN) radio <b>28800</b>. The Ethernet switch <b>28300</b> connections are made using a collection of four-conductor Ethernet busses <b>28606</b>. The LAN radio is connected to a LAN radio antenna <b>28806</b>, a switch <b>28802</b>, and a radio key <b>28804</b>, which may be employed to enable certain functions on secure radios such as JTRS radios. The head <b>2800</b> includes a head latch control <b>28102</b>, which may be operable to enable opening of the head housing or disconnection from the neck.

Head connector <b>28600</b> connections for FARnet <b>28208</b>, PMBus <b>28604</b>, and Ethernet bus <b>28606</b>. Head connector <b>28600</b> also includes a differential NSTC signal conductor <b>28610</b> and a two-conductor power conductor <b>28608</b>. Head payload connector <b>28700</b> includes connections for FARnet <b>28208</b>, PMBus <b>28604</b>, Ethernet bus <b>28606</b>, and power conductor <b>28608</b>. In this embodiment, the power provided on conductors <b>28608</b> is converted by the four depicted DC-DC converters, shown as <b>28004</b> through <b>28010</b>. VSTBY is standby voltage. The second depicted 3.3V out converter supplies the digital logic such as the SBC <b>28100</b> (3.3V external) and audio codec <b>28404</b>. The third depicted converter supplies 5V output to as needed to circuits such as the radio <b>28800</b> and sensors and cameras <b>28902</b>, <b>28904</b>, <b>28906</b>, and <b>28908</b>. The fourth depicted converter <b>28010</b> supplies various voltages required to operate FPQA <b>28200</b> (3.3V).

<figref idrefs="DRAWINGS">FIG. 37</figref> is a block diagram <b>2900</b> of one possible embodiment of a first tilt module <b>2902</b>. Tilt modules of this design may be used to implement the various tilt axes employed in robots designs herein toward the distal end of the robot's neck. Module <b>2902</b> houses one or more circuit boards or circuit modules. Rigid circuit boards, flexible polyimide circuits, or other circuit modules or combinations may be used. The depicted module <b>2902</b> has various motors and sensors mounted therein or thereto, and is typically itself mounted to a robot neck extension such as those described herein. Module <b>2902</b> may electrically connect to the robot head <b>28002</b> through electrical connections provided in a head connector <b>2904</b>, and these connections may include a four-conductor FARnet bus <b>2960</b>, a four-conductor Ethernet bus <b>2964</b>, a 2-conductor PMBus <b>2966</b>, a differential NSTC bus <b>2968</b>, and 2-conductor power bus <b>2970</b>. Busses <b>2960</b> through <b>2970</b> are also electrically connected to a slip ring <b>2890</b>. Power bus <b>2970</b> is electrically connected to DC-DC converters <b>2912</b> and <b>2914</b>, and these converters <b>2912</b> and <b>2914</b> provide power for the electrical components included in first tilt module <b>2902</b>.

An FPGA <b>2950</b> is provided in module <b>2902</b> to perform various digital logic and data routing functions such as multiplexing the video or sensor signals to appropriate destinations, as well as, in this embodiment, interfacing to the actuator data communications bus known as FARnet. In a preferred embodiment, FPGA <b>2950</b> is a XC3S500. FPGA <b>2950</b> is connected to oscillator <b>2924</b>, an EEPROM <b>2928</b>, and RS485 transceivers <b>2926</b> and <b>2930</b>. Transceivers <b>2926</b> and <b>2930</b> are in communication with FARnet bus <b>2960</b>. The depicted FARnet busses are actuator control busses that, in one embodiment, are RS-485 serial busses. Their interconnection herein forms a noded network of actuators. The FARnet bus scheme preferably operates as a noded scheme rather than detecting collisions on a common bus, but a common bus scheme may be used. In this embodiment, each node receives commands, implements the commands addressed to itself, and forwards the other commands along the FARnet network.

Module <b>2902</b> also includes components used for motion control, such as a pair of h-bridge drivers <b>2920</b> and <b>2922</b>. Other motion control components included in the first tilt module <b>2902</b> include an h-bridge <b>2916</b>, a current sense module <b>2918</b>, an ADC <b>2932</b>, a first tilt encoder <b>2934</b>, and an encoder magnet <b>2936</b>. The depicted encoders at each actuator herein are preferably absolute position encoders rather than (or in conjunction with) differential encoders. Such encoders allow absolute position controlling of the actuated joints. This scheme is advantageous especially when combined with the slip clutches described herein which may prevent reliance on differential encoder tracking in some situations. Other motion control components include a thermistor <b>2906</b>, a brushless motor <b>2908</b>, and a collection of hall sensors <b>2910</b>.

<figref idrefs="DRAWINGS">FIG. 38</figref> is a block diagram <b>3000</b> of one possible embodiment of a pan module <b>3002</b>. A pan module of this design may implement pan axes along a robot's neck according to various designs herein. The module <b>3002</b> houses one or more circuit boards or circuit modules. Rigid circuit boards, flexible polyimide circuits, or other circuit modules or combinations may be used. The depicted module <b>3002</b> has various motors and sensors mounted therein or thereto, and is typically itself mounted to a robot neck extension such as those described herein. Module <b>3002</b> may electrically connect to the robot head <b>2902</b> through electrical connections provided in a slip ring <b>3080</b>. Slip ring <b>3080</b> is preferably electrically coupled to slip ring <b>2980</b> (<figref idrefs="DRAWINGS">FIG. 37</figref>) with a passthrough connector passing through the interior of the depicted upper curved portion of pan link <b>4308</b> (<figref idrefs="DRAWINGS">FIG. 27</figref>). Such connections may include a four-conductor FARnet bus <b>3010</b>, a four-conductor Ethernet bus <b>3036</b>, a 2-conductor PMBus <b>3038</b>, a differential NSTC bus <b>3040</b>, and 2-conductor power bus <b>3042</b>. Busses <b>3010</b>, <b>3036</b>, <b>3038</b>, <b>3040</b>, and <b>3042</b> are also electrically connected to a slip ring <b>3050</b>. Power bus <b>3042</b> is electrically connected to DC-DC converters <b>3044</b> and <b>3046</b>, and these converters <b>3044</b> and <b>3046</b> provide power for the electrical components included in pan module <b>3002</b>.

Depicted in <figref idrefs="DRAWINGS">FIG. 38</figref>, an FPGA <b>3004</b> is provided in robot tilt module <b>3002</b> to perform various digital logic and data routing functions such as multiplexing the motion control or sensor signals to appropriate destinations, as well as, in this embodiment, interfacing to the actuator data communications bus known as FARnet. In a preferred embodiment, FPGA <b>2950</b> is a XC3S500. FPGA <b>3004</b> is connected to oscillator <b>3012</b>, an EEPROM <b>3014</b>, and RS485 transceivers <b>3006</b> and <b>3008</b>. Transceivers <b>3006</b> and <b>3008</b> are in communication with FARnet bus <b>3010</b>.

Pan module <b>3002</b> also includes components used for motion control, such as a pair of half bridge drivers <b>3016</b> and <b>3018</b>. Other motion control components included in the pan module <b>3002</b> include an h-bridge <b>3022</b>, a current sense module <b>3024</b>, an ADC <b>3020</b>, a pan encoder <b>3034</b>, and an encoder magnet <b>3032</b>. Other motion control components include a thermistor <b>3026</b>, a brushless motor <b>3028</b>, and a collection of hall sensors <b>3030</b>.

<figref idrefs="DRAWINGS">FIG. 39</figref> is a block diagram <b>3100</b> of a robot lower neck assembly according to one embodiment. The assembly <b>3100</b> includes the entire lower neck assembly from the chassis or base attachment <b>3192</b> including shoulder or “collar” actuator <b>4302</b> (<figref idrefs="DRAWINGS">FIG. 27</figref>) and first tilt actuator <b>4306</b> (<figref idrefs="DRAWINGS">FIG. 27</figref>). In this embodiment, the assembly <b>3100</b> is represented as a combined lower neck assembly module <b>3102</b> housing both shoulder actuator and first tilt actuator modules, shown together in this case because the depicted circuits do not move with respect to each other. The lower neck assembly module <b>3102</b> includes one or more circuit boards or circuit modules and both sets of actuator motors and gears. Rigid circuit boards, flexible polyimide circuits, or other circuit modules or combinations may be used. The depicted module <b>3102</b> has various motors and sensors mounted therein or thereto, and is typically itself mounted to a robot neck extension such as those described herein. Module <b>3102</b> may electrically connect to the pan module <b>2902</b> through electrical connections provided in slip ring <b>3050</b>. Such connections may include a four-conductor FARnet bus <b>3110</b>, a four-conductor Ethernet bus <b>3150</b>, a 2-conductor PMBus <b>3152</b>, a differential NSTC bus <b>3155</b>, and 2-conductor power bus <b>3154</b>. Busses <b>3150</b>, <b>3152</b>, and <b>3155</b> are also electrically connected to a collar connector <b>3180</b>. Power bus <b>3154</b> is electrically connected to DC-DC converters <b>3162</b> and <b>3164</b>, and these converters <b>3162</b> and <b>3164</b> provide power for the electrical components included in shoulder tilt module <b>3102</b>. Power bus <b>3154</b> is also electrically connected to a linear regulator <b>3156</b> and a bus buffer <b>3158</b>, and regulator <b>3156</b> and buffer <b>3158</b> both electrically connect to a power module <b>3160</b>.

Depicted toward the center of the block diagram in <figref idrefs="DRAWINGS">FIG. 39</figref> is FPGA <b>3104</b>, which is provided in module <b>3102</b> to perform various digital logic and data routing functions such as multiplexing the motion control or sensor signals to appropriate destinations, as well as, in this embodiment, interfacing to the actuator data communications bus known as FARnet. In a preferred embodiment, FPGA <b>3104</b> is a XC3S500. FPGA <b>3104</b> is connected to oscillator <b>3112</b>, an EEPROM <b>3114</b>, and RS485 transceivers <b>3106</b> and <b>3108</b>. Transceivers <b>3106</b> and <b>3108</b> are in communication with FARnet bus <b>3110</b>. FPGA <b>3104</b> and its associated transceivers perform as a single FARnet node which receives control signals addressed to each of first tilt module actuator motor <b>3138</b> and shoulder tilt module actuator motor <b>3140</b>.

Lower neck assembly module <b>3102</b> also includes components used for motion control, such as four half bridge drivers <b>3116</b> through <b>3122</b>. In a preferred embodiment, h-bridge drivers <b>3116</b> through <b>3122</b> are Intersil HIP2101. Other motion control components included in the module <b>3102</b> include a pair of h-bridges <b>3126</b> and <b>3128</b>, a pair of current sense modules <b>3130</b> and <b>3132</b>, an ADC <b>3124</b>, a first tilt encoder <b>3168</b>, a first tilt encoder magnet <b>3116</b>, a clavical encoder <b>3172</b>, and a clavical encoder magnet <b>3170</b>. Other motion control components include a pair of thermistors <b>3134</b> and <b>3136</b>, a pair of brushless motors <b>3138</b> and <b>3140</b>, and a collection of hall sensors <b>3142</b> and <b>3144</b>. Electrical connection from assembly <b>3102</b> to the robot base <b>3190</b> is made through a slip ring <b>3174</b> and color connector <b>3180</b>. Slip ring <b>3174</b> allows connectivity despite actuator movement of the shoulder joint. The depicted collar connectors <b>3180</b> and <b>3192</b> represent the connectors that join the neck to the chassis (<figref idrefs="DRAWINGS">FIG. 35A-C</figref>).

<figref idrefs="DRAWINGS">FIG. 40</figref> shows a block diagram <b>3200</b> for one possible embodiment of a robot chassis or base <b>3202</b>. Preferably, base <b>3202</b> generally houses the power supply (such as batteries) and much of the power control circuitry for portable robot designs herein. The base <b>3202</b> may electrically connect to the robot neck at (module <b>3102</b>) through electrical connections provided in a collar connector <b>3250</b>. Such connections may include a first four-conductor FARnet bus <b>3208</b>, a four-conductor Ethernet bus <b>3222</b>, a 2-conductor PM Bus <b>3254</b>, and a 2-conductor power bus <b>3228</b>.

Centrally located in <figref idrefs="DRAWINGS">FIG. 40</figref>, an FPGA <b>3204</b> is provided in the base circuit <b>3202</b> to perform various digital logic and data routing functions such as multiplexing the motion control or sensor signals to appropriate destinations, as well as, in this embodiment, interfacing to the actuator data communications bus known as FARnet. In a preferred embodiment, FPGA <b>3204</b> is a XC3S1000. FPGA <b>3204</b> is connected to a pair of RS485 transceivers <b>3206</b>. Transceivers <b>3206</b> are in communication with first FARnet bus <b>3208</b> and a second FARnet bus <b>3209</b>.

Base <b>3202</b> also includes components used for motion control, such as an ADC <b>3208</b>, a flipper absolute encoder <b>3270</b>, a flipper motor driver <b>3272</b>, a drivel motor driver and, battery charger <b>3274</b>, and a drive2 motor driver and battery charger <b>3276</b>. Other motion control components include a set of three thermistors <b>3286</b>, <b>3287</b>, and <b>3288</b>, a pair of BLDC motors <b>3292</b> and <b>3293</b>, a flipper brushless motor <b>3284</b>, a set of three incremental encoders <b>3280</b>, <b>3281</b>, and <b>3282</b>, a brake <b>3291</b>, and a collection of hall sensors <b>3289</b> and <b>3290</b>.

Base <b>3202</b> also includes other various components used for power and communications, such as fiber connector <b>3212</b> which is optically connected to fiber optic transceiver <b>3214</b> for connection of remote control tethers. Transceiver <b>3214</b> converts the fiber optic based communications to four-conductor electrical communications, and the Ethernet bus that carries this converted communications is electrically connected to an Ethernet switch <b>3210</b>. Ethernet switch <b>3210</b> is connected to EEPROM <b>3216</b>. Ethernet switch <b>3210</b> is in electrical communication with a maintenance port connector <b>3260</b>, a collar connector <b>3250</b> via a first isolation transformer <b>3220</b>, and a payload connector A (<b>3252</b>) via a second isolation transformer <b>3220</b>. A collection of payload power switches <b>3226</b> electrically connects to collar connector <b>3250</b> via power bus <b>3226</b>, payload connector <b>3252</b> via a 2-conductor power bus <b>3256</b>, and asset of power switches and ideal diodes <b>3242</b>. Payload power switches <b>3226</b> is also electrically connected to a power microcontroller <b>3238</b>, which is also connected to the power switches and ideal diodes <b>3242</b>. The base <b>3202</b> also includes a collection of power regulators and local controls <b>3230</b> for controlling drive motors and other functions in base <b>3202</b>, such as flipper movement, for example. Payload connector <b>3252</b> also includes electrical conductors for PM Bus <b>3254</b>.

Visible in the left-central area of <figref idrefs="DRAWINGS">FIG. 32</figref> is a I2C switch complex programmable logic device (CPLD) <b>3232</b>. CPLD <b>3232</b> is electrically connected to a battery connector <b>1</b><b>3262</b> via opto-isolator <b>3234</b>, and a battery connector <b>3264</b> via opto-isolator <b>3244</b>.

<figref idrefs="DRAWINGS">FIG. 41</figref> illustrates an embodiment of a robot <b>3300</b> that comprises a head <b>3302</b>, a neck <b>3304</b> in a stowed position, a pan link <b>3306</b> in an extended position, a set of flipper tracks <b>3308</b>, and a set of drive tracks <b>3310</b>. The robot is depicted in a low-profile pose. In this configuration, the robot <b>3300</b> is able to maintain a low overall profile while still allowing the head <b>3302</b> to pan horizontally without colliding with any other part of the robot <b>3300</b>. This configuration may be useful for situations such as inspecting the undersides of vehicles, buildings, inspecting culverts and other such confined spaces, roving underneath fences, and similar tasks. If a lower profile is required for roving, the pan link <b>3306</b> may be rotated into a stowed position in order to gain additional clearance. Placing the pan link <b>3306</b> in a stowed position may also allow the robot <b>3300</b> to achieve a highly compact stowed position for storage and/or transport.

The depicted pose in <figref idrefs="DRAWINGS">FIG. 41</figref> may be further described with reference to the position of the various actuated joints shown in <figref idrefs="DRAWINGS">FIG. 27</figref>. Pursuant to independent commands propagated along the networks to the independent motor modules, as shown in <figref idrefs="DRAWINGS">FIG. 41</figref>, actuated tilt joint <b>4302</b> rotates itself to orient the neck flat or slightly elevated from flat. A flat backward angle with respect to the chassis may be described as the base or 0° position of actuated tilt joint <b>4302</b>. Actuated tilt joint <b>4306</b> rotates itself to orient the pan link to a substantially 90° angle from neck <b>3304</b>. Actuated pan joint <b>4308</b>, to achieve the depicted pose, rotates itself to its 0° pan position, that is with the robot sensor face oriented toward the front of the robot. This pose allows, of course, panning movement in pan axis <b>4308</b>. Actuated tilt joint <b>4310</b> rotates itself to its base or 0° tilt position, that is with the depicted sensor face oriented at a 90° angle from the depicted vertical portion of pan link <b>3306</b>.

<figref idrefs="DRAWINGS">FIG. 42</figref> illustrates an example of robot <b>3300</b> in another possible position. In this configuration, the robot <b>3300</b> is largely horizontal with the neck <b>3304</b> and head <b>3302</b> positioned in a largely vertical position. Pan link <b>3306</b> may also be extended in order to achieve additional height for the head <b>3302</b>. This stance may be useful for maintaining a stable position while observing over obstacles, inspecting tabletops, observing though automobile windows, navigating through vegetation, navigating through low-hanging fog or other gasses, etc.

To achieve the depicted pose, pursuant to independent commands propagated along the network to the independent motor modules, flippers <b>3308</b> orient themselves in an upright 90° position. Referring again to the joints described in <figref idrefs="DRAWINGS">FIG. 27</figref>, actuated tilt joint <b>4302</b> rotates itself to orient the neck at the 90° upright position. Actuated tilt joint <b>4306</b> rotates itself to orient the pan link <b>3306</b> at a 0° parallel angle to neck <b>3304</b>. Actuated pan joint <b>4308</b>, if needed, rotates itself to its 0° pan position. Actuated tilt joint <b>2310</b> rotates itself to its 0° tilt position.

<figref idrefs="DRAWINGS">FIG. 43</figref> depicts robot <b>3300</b> in a possible position that may be suitable for inspecting the entrance to a hole, cave, manhole, culvert, or other such opening that may be below the plane of the ground around it. This illustration shows that robot <b>3300</b> is capable of placing the neck in a position such that the head is positioned below the plane of the drive tracks <b>3310</b>. Pan link <b>3306</b> may also be extended to position the head <b>3302</b> an additional distance below the ground plane. In the depicted position, robot <b>3300</b> may be able to observe objects underneath the surface that it is resting upon. With pan link <b>3306</b> extended downward, the robot <b>3300</b> is able to turn head <b>3302</b> and observe in several directions, for example, through a hole in a floor.

The depicted pose in <figref idrefs="DRAWINGS">FIG. 43</figref> may be further described with reference to the position of the various actuated joints shown in <figref idrefs="DRAWINGS">FIG. 27</figref>. Actuated tilt joint <b>4302</b> rotates itself to orient the neck to an angle of about 210° or greater. The depicted pose may require actuated tilt joint <b>4302</b> to rotate to its greatest allow extent. Actuated tilt joint <b>4306</b> rotates itself to orient the pan link to a substantially 30 to 45° angle from neck <b>3304</b>. Actuated tilt joint <b>4310</b> rotates itself to substantially 5 to 10° forward of its base position. This angle may of course vary depending on whether the pose is looking into a hole, underneath a balcony, or inspecting the underside of its own supporting surface, for example. A backward angle may be used to observe in a hole. A greater angle around 15 to 30° would be needed to inspect the underside of its supporting surface.

<figref idrefs="DRAWINGS">FIG. 44</figref> depicts robot <b>3300</b> in a possible position where the neck <b>3304</b> is in a largely forward position and head <b>3302</b> is rotated to one side. This position may be useful for observing around corners or other such obstacles while keeping the rest of the robot <b>3300</b> protected or out of view. In use, an operator may move the robot toward a corner until it detects the stopping point, at a designated distance to present the extended neck beyond the corner. Then the operator commands the robot to move to the depicted extended position for around-corner viewing.

The depicted pose in <figref idrefs="DRAWINGS">FIG. 44</figref> may also be described with reference to the position of the various actuated joints shown in <figref idrefs="DRAWINGS">FIG. 27</figref>. Actuated tilt joint <b>4302</b> rotates itself to orient the neck at substantially a 180° to 190° angle from its 0° position. Actuated tilt joint <b>4306</b> rotates itself to orient the pan link to substantially 0 to 10° backward angle from neck <b>3304</b>, needed to compensate for greater than 180° angle of neck. Actuated pan joint <b>4308</b>, to achieve the depicted pose, rotates itself to a 90° right pan position. A pose for looking around corners to the left would of course be achieved by rotating actuated pan joint to a 90° left position.

<figref idrefs="DRAWINGS">FIG. 45</figref> depicts robot <b>3300</b> in another possible position. In this configuration, neck <b>3304</b>, and pan link <b>3306</b> are tilted rearward and the second tilt axis <b>4310</b> (<figref idrefs="DRAWINGS">FIG. 27</figref>) is tilted forward so that the sensor face of head <b>3302</b> has a forward view. This position may achieve the minimum possible overall height for the robot <b>3300</b>, and may be useful for inspecting the underside of vehicles, buildings, etc., for navigating under or though passages that require low clearance, etc.

The depicted pose in <figref idrefs="DRAWINGS">FIG. 45</figref> may also be described with reference to the position of the various actuated joints shown in <figref idrefs="DRAWINGS">FIG. 27</figref>. Actuated tilt joint <b>4302</b> rotates itself to orient the neck slightly elevated from the flat or 0° position, for example, about 5°. Actuated tilt joint <b>4306</b> rotates itself to orient the pan, link <b>3306</b> backward to a substantially 15 to 20° angle from neck <b>3304</b>. Actuated pan joint <b>4308</b> rotates itself to its 0° pan position. Actuated tilt joint <b>4310</b> rotates itself as far forward of its 0° or upright position is possible without interference with pan link <b>3306</b>, preferably up to a 90° forward rotation. This angle preferably orient the sensor face close to parallel with the pan link <b>3306</b>.

<figref idrefs="DRAWINGS">FIG. 46</figref> depicts robot <b>3300</b> in a position where neck <b>3304</b> is placed in a largely forward position, and the head <b>3302</b> is rotated such that the head <b>3302</b> faces the robot <b>3300</b>. This position may be useful for inspecting the front of the tracks or the underside of robot <b>3300</b>.

The depicted pose in <figref idrefs="DRAWINGS">FIG. 46</figref> may also be described with reference to the position of the various actuated joints shown in <figref idrefs="DRAWINGS">FIG. 27</figref>. Actuated tilt joint <b>4302</b> rotates itself to orient the neck at substantially a 180° to 190° angle from its 0° position. Actuated tilt joint <b>4306</b> rotates itself to orient the pan link to substantially 70 to 80° forward angle with respect to the neck. Actuated pan joint <b>4308</b> rotates itself to its 0° pan position. Actuated tilt joint <b>4310</b> or take itself substantially 10° forward of its base position to orient a sensor face back toward a robot chassis. Preferably the movements of actuated tilt joints <b>4306</b> and <b>4310</b> precede the final movement of actuated tilt joint <b>4302</b> to avoid the floor interfering with head movement. Such coordinated movement may be provided as a preprogrammed sequence to obtain a preset position which, like the other positions described herein, may be mapped to a remote operator control unit button or menu as a preset position.

<figref idrefs="DRAWINGS">FIG. 47</figref> depicts robot <b>3300</b> in another possible position. In this position, neck <b>3304</b> is in a largely vertical position and head <b>3302</b> is in a downward-facing position. This stance may be useful for inspecting flipper tracks <b>3308</b>, drive tracks <b>3310</b>, or other parts of the robot <b>3300</b>.

The depicted pose in <figref idrefs="DRAWINGS">FIG. 47</figref> may also be described with reference to the position of the various actuated joints shown in <figref idrefs="DRAWINGS">FIG. 27</figref>. The depicted pose, like the others here shown herein, is preferably achieved pursuant to independent commands propagated along the network to the independent motor modules. Referring again to the joints described in <figref idrefs="DRAWINGS">FIG. 27</figref>, actuated tilt joint <b>4302</b> rotates itself to orient the neck at the 90° upright position. Actuated tilt joint <b>4306</b> rotates itself to orient the pan link <b>3306</b> at a 0° parallel angle to neck <b>3304</b>. Actuated pan joint <b>4308</b>, rotates itself to substantially a 90 to 100° right-hand pan position. Further panning may provide inspection of rearward portions of the right-hand track. Actuated tilt joint <b>2310</b> rotates itself to substantially a 45° downward tilt position from its 0° upright position.

<figref idrefs="DRAWINGS">FIG. 48</figref> illustrates an example of robot <b>3300</b> in another possible position. The depicted robot <b>3300</b> is shown “standing” or oriented largely vertically to elevate the sensor head as high as possible. Such a pose may be useful for observation or radio transmission, for example. The depicted pose may be made leaning against a wall or is other obstacle, or in some embodiments may be achieved with the use of rear flippers such as those disclosed above. The flipper angle to the wall shown is not exclusive, and a much lower angle may be employ to more align the flippers with the robot chassis. To enter the depicted pose, the robot <b>3300</b> may be navigated to contact a wall or other similar surface, and using a set of flipper tracks <b>3308</b> the robot <b>3300</b> may “climb” up the wall in order to achieve a largely vertical stance. To begin the climbing operation, the neck may be pivoted backward to a position substantially 30° up from its flat, stowed position by actuated joint <b>4302</b> (<figref idrefs="DRAWINGS">FIG. 27</figref>) to help alter the center of gravity for the robot <b>3300</b> in order to enhance climbing capability. Preferably, as the chassis climb angle increases, the neck is pivoted upward to eventually reach its depicted angle.

The depicted pose in <figref idrefs="DRAWINGS">FIG. 48</figref> may also be described with reference to the position of the various actuated joints shown in <figref idrefs="DRAWINGS">FIG. 27</figref>. To achieve the depicted pose, pursuant to independent commands propagated along the network to the independent motor modules, flippers <b>3308</b> orient themselves downward from a forward position parallel to the chassis. Depending on the obstacle and friction of the surface is involved the angle may be anywhere from 0° to 90° forward rotation. Slight backward rotation may also be used. Referring again to the joints described in <figref idrefs="DRAWINGS">FIG. 27</figref>, actuated tilt joint <b>4302</b> rotates itself to orient the neck at substantially a 165-170° forward rotation, to orient the neck <b>3304</b> and substantially vertical position from the ground. Actuated tilt joint <b>4306</b> rotates itself to orient the pan link <b>3306</b> at a 0° parallel angle to neck <b>3304</b>. Actuated pan joint <b>4308</b> rotates itself to its 180° pan position. In the depicted pose, actuated pan joint <b>4308</b> may rotated in all directions for observation. Actuated tilt joint <b>4310</b> rotates itself to substantially its 0° tilt position.

<figref idrefs="DRAWINGS">FIG. 49</figref> is an illustration that depicts robot <b>3300</b> in another possible position. In this example, the robot <b>3300</b> is largely horizontal, the neck <b>3304</b> is placed in a largely forward position, and the head is in an upward-facing position. This stance may be useful for inspecting the undersides of objects, for peering upward from underneath an obstacle with low clearance, and other similar tasks.

The depicted pose in <figref idrefs="DRAWINGS">FIG. 49</figref> may also be described with reference to the position of the various actuated joints shown in <figref idrefs="DRAWINGS">FIG. 27</figref>. Actuated tilt joint <b>4302</b> rotates itself to orient the neck at substantially a 180 to 190° angle from its 0° position. Actuated tilt joint <b>4306</b> rotates itself to orient the pan link to substantially 100 to 115° backward angle from neck <b>3304</b>. Actuated pan joint <b>4308</b>, to achieve the depicted pose, rotates itself to substantially a 0° forward pan position left and right panning motion may be employed in the depicted pose. Actuated tilt joint <b>4310</b> rotates itself to substantially its 35 to 45° backward tilt position.

<figref idrefs="DRAWINGS">FIG. 50</figref> depicts a flow chart for moving to preset positions. Any of the positions described herein, and other positions, may be set as preset conditions. Typically, a preset position may be selected by an operator or an autonomous control program in response to operating conditions or scenarios. Preferably, an operator selects preset positions by selecting a preset button or combination, or selecting the position from a control menu as will be further described. In the depicted flow chart, robot <b>3300</b> receives a present position command at its control computer in step <b>4301</b>. Such a command may also be generated by autonomous control programs running on the control computer or a remotely-located control computer. The controller then transmits actuator control signals in step <b>4302</b> to enter the preset position. In various embodiments such control signals may take various forms, such as absolute position commands to particular actuators, or the controller may sense a present actuator position and issue relative commands. Such sensing may be left to local actuator control circuitry. The preset position commands may be sent to the shoulder and neck actuators as described herein, but may also move the robot flippers and tracks to certain present positions or movement scenarios. For example, a particular operator command may be present to carry out a specific sequence such as an obstacle climbing sequence involving a series of movements by one or more actuators as well as track movements.

Preferably, actuator position commands are transmitted over a nodded actuator network such as the FARnet network described herein. Other suitable control bus schemes may be used. In step <b>4303</b> the various actuators move to their preset positions. Movement may be simultaneous or may be in a pre-designated order necessary to achieve a particular desired movement sequence. For example, for the center of gravity shifting (CG-shifting) positions described herein, certain head and neck movements may be needed in a particular position to achieve desired CG-shifting movements appropriate for particular climbing sequences.

Other robotic vehicle details and features combinable with those described herein may be found in a U.S. Provisional application filed concurrently herewith, entitled “Robotic Vehicle With Dynamic Range Actuators” and assigned Ser. No. 60/878,877, the entire contents of which are hereby incorporated by reference for all purposes.

A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, various construction materials may be used. Further, other techniques besides the depicted neck and head designs may be employed to do center of gravity shifting. Accordingly, other variations are within the scope of the following claims.